Experienced users of Scid

I'm looking for very experienced users of Scid 4.7 and newer. To ask some questions about the usage. Because think the included manual is not very good. 
I have some question about the option to mark games with flags like "white opening" or "black opening".
Also if you compact game database it changes the order of the games. How can I avoid this.
How can I sort a database by date (oldest first), and fix the sort order. Choose to import new games at te end of the  database so the database keep sorted by date?
I have many more questions. I like Scid verry much because it is very fast and it's free. 

I prefer Scid 4.7 over Scid vs PC, besaus Scid 4.7 is faster and can handle huge pgn datababases with more than 10 million games.

Scid and Scid vs Pc don't detect doubles when the player names ar different. I wonder if there is some way around? I could remove the player names, but than that's lost forever. I wonder if it would be possible to replace white with wh, and black with bl, in the game header, with a text editing tool that can handle huge huge text files like Ultra Edit or SED.
And then search for doubles in Scid.

There's a very good tool for replacing names, so if you have a lot of games one way and want them to be something else, you can change them. 

The duplicate game filter also is pretty good and let's you define what you consider duplicates (in SCID vs PC for sure). You might be able to ignore names in the checks.

How do you replace names with Scid? Do you mean with the spellcheck option for player names with Scid? I don't know how this option works. I have huge pgn databases with games fro lichess downloaded from different sources. And I want to put them to gether and remove duplicates. Also when its a game with exact the same moves but with different player names becouse of misspelling in the duplicated game. There is no option in Scid and Scid for Pc, to ignore player names when checking for doubles. I have send an email to the programmer of Scid for PC to request this but for some reason doesn't think that is usefull. You schould have atleast have an option to ignore player names when checking for duplicates, I think. 

I've used the Maintenance options. I'm not near my system with the application, but will try to remember to look later and verify. I've used it on my personal database where I've sometimes not been consistent in naming, to replace the mismatches with my preferred name(s).

So, you're right on the twin checker. At least in SCID vs PC your options are full name match or matching the first 4 characters. So if you have something completely different, that won't be an option.

For the name issue, there is a Spell Checker option in the maintenance, so depending on what the issue is, that might be able to fix some.  Or you can use Name Editor to search and replace certain names options. In the Replace field you can start typing something and it will show matches in the  DB. You can select one of those then type what you want to replace it With