Is the Winawer or the Classical French more theory to learn for black?

I ask myself if the Winawer or the Classical French e.g Steinitz vs 4.e5 and the Mac Cutcheon or Burn vs 4.Bg5 is more to learn from the blackside perspective

Winawer is less theory than the combination of Classical and McCutcheon.

The McCutcheon on its own is sharp and forcing like the Winawer.

Also, the Classical and McCutcheon lead to very different positions, so you would be taking on a lot more "variety" in positions than just learning the Winawer alone. Neither good or bad to have to learn more structures. Depends on your goals.

At least online it seems that 50% go for the Exchange variation, 30% for the advance, 25% for the Tarrasch and only 5% for 3. Nc3. To be honest i only really studied the advance and the exchange variation. The Tarrasch and the Winawer just a little bit. My current repertoire is the Winawer Schullmann line. I anyway wanted to probably stay with my repertoire but was just wondering if the classical and Mac Cutcheon might be less theory.

What I like about the Winawer is that people go for sidelines. What do you think about the Schulmann variation as answer to the Mainline Winawer?

 Wow I'm surprised to hear you face 3. Nc3 so rarely.

By the Schulmann are you referring to 1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3+ 6. bxc3 Qa5 7. Bd2 Qa4?

Interesting line and considering how you say people rarely reach the 5. Bxc3+ tabiya it seems smart to go for a sideline you'll understand better than your opponent instead of having to remember complicated poisoned pawn mainlines that you don't get any chance to practice and get familiar with.

This is vastly inaccurate!

First off, you do not need to know the Classical and the McCutchen.  One or the other!  What you need to know is the Steinitz and EITHER the Classical OR McCutchen.

Second, the Winawer is NOT less theory by any stretch of the imagination.

The Steinitz sees the moves 1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.e5 Nfd7 5.f4 c5 6.Nf3 Nc6 7.Be3 and now Black needs to study ONE (not all) of the following:  7...cxd4, 7...a6, 7...Qb6, 7...Be7

Now you need to know what to do against 4.Bg5.  You have 3 choices.  The McCutchen, the Burn, or the Classical.  The McCutchen has the most theory of the 3.  The burn is the least forgiving to errors.  The Classical is the easiest.

In the McCutchen, you need to know 6.Bd2, 6.Be3, 6.Bc1, the fashionable but dubious 6.Bf4, the dubious 6.Bh4, and the innocuous 6.exf6.  In addition, after 4.Bg5 Bb4, you must know the sideline 5.exd5, and that this is the one time that you MUST take back with the QUEEN!  5...exd5 exd5? 6.Qf3 +-.

The Burn has its own theory and you must know it or you will lose - not recommended.

The Classical sees 4.Bg5 Be7 and now you have 5.exd5 exd5, and 5.e5 Nfd7.  After the latter, you need to know 6.Bxe7 and a line against 6.h4 (Alekhine-Chatard Attack).  The other sideline is 5.Nf3 instead of 5.f4, but that is just a transposition to the Two Knights French (1.e4 e6 2.Nf3 d5 3.Nc3 Nf6 4.e5 Nfd7 5.d4 is the same position).

Also of note, after 3.Nc3 Nf6, if 4.exd5 immediately, then 4...exd5! And if 5.Bg5, Black must play 5...Be7, going the Classical route, NOT 5...Bb4 due to 6.Qf3 again!  So if you play the McCutchen, you must know the Exchange line in the Classical.

All of that said, if you want the least theory, I would suggest the Steinitz combined with the Classical.  Here is what you need to know to play the Winawer:

1.e4 e6 2.d4 d5 3.Nc3 Bb4 and now:

A) 4.exd5

B) 4.Nge2

C) 4.Qg4

D) 4.Qd3

E) 4.Bd2

F) 4.a3 Bxc3+ 5.bxc3 dxe4 and now

F1) 6.f3

F2) 6.Qg4

G) 4.Bd3

H) 4.e5 and now I recommend 4...Ne7 first and 6...c5 rather than 4...c5 and 6...Ne7 because of the line 4...c5 5.Bd2, which is annoying with lots of theory.  After 4...Ne7 5.Bd2, 5...b6 is strong.  So after 4...Ne7 5.a3 Bxc3+ 6.bxc3 c5, you have:

H1) 7.Nf3

H2) 7.a4

H3) 7.h4!

H4) 7.Qg4 and now you must know one of 7...Qc7 (which White can play 8.Qxg7 or 8.Bd3), 7...O-O, 7...Kf8, or 7...Nf5.

There is a LOT more theory in the Winawer than the Steinitz and Classical (4...Be7) COMBINED!

You want the least theory, Classical and Steinitz is the way to go!

Least theory is no valid criterion. Seen in that light 3...c6, 3...Ne7, 3...a6, 3...Be7, 3...Nc6 are more appealing. Especially 3...Nc6 is not bad
https://www.chessgames.com/perl/chessgame?gid=1044354 
Usually the better lines are played more and thus have more theory.
3...dxe4 is good too.
To answer the question: Winawer has more theory than classical.

Yes exactly

Thanks for the detailed answer. What line in the Steinitz would you recommend and what do you think about 6.Be7?

If it helps at the moment i am studying mostly IQP/Hanging pawns and Carlsbad structures because these are the structure i get most often on the board.

Vs. 1.d4 i play the QGD because its imo maybe together with the slav the easiest good defense vs 1.d4

50% + 30% + 25% + 5% =???????

Stop getting this mindset that I shouldn't play this opening because of theory. Chances are, your opponent doesn't know theory and even though I know a decent amount of theory, you still need to be able to manage the middlegame and endgames. All theory gets is equalize or get an advantage in the opening few moves, that's it. Also, you learn as you go. I know the Botvinnik Semi-Slav (the most complex opening) up to at least move 16 but I can tell you that it's almost useless when people play natural developing moves.

The Winawer follows the basic Chess principles of developing your pieces to good squares. Play that

If you want less theory, the rubinstein (3..dxe4) is the way to go against Nc3. If you want to win with it  though you need to be prepared to outplay your opponent in equal endgames or hope your opponent presses too hard to win.

I used to play 3...Nf6 and the gf6 Burn, and when I played that I used exactly the line pfren mentioned above. I had ok results for the most part. I spent a lot of time studying theory and learning my lines, because if you play the Burn carelessly (especially in blitz) white may break through with d5 or something in the opening and your position can become a mess. But over the board it worked out well for me. Most people probably wouldn't want to put in as much work into studying those lines as I did, though. 

I'd add that on 3...Nf6 I'm quite convinced 4. e5 is the most challenging move and I think white has good chances of an advantage. I'm not sure that matters for our purposes here; the Be7 dc5 Qa5 stuff worked ok for me and I had some good prep. I've played the Winawer as well, long time ago. It's been a while though and maybe I'll come back to it sometime soon