Why you have only 50 minutes should be looked at. That is not enough time to play. You could have a 2pm or so start on the weekend and whoever shows up shows up. If some come at 5pm, then they play and anyone else there could play too. They could finish one game and then take a break for a new group to be formed.
Since you mentioned a rating range of 600 and 2100, I would put them into into different groups of under 1000, under 1700 and then I guess under 2300. This way you aren't explaining the rules to 1500+ players who already know. They can use the 10 minutes for something else.
I want to help the people at my club get better, so I'm making a powerpoint to teach people chess. However we only meet 36 times a year, and we only have ~50 minutes, so I don't want to take up more than 10 minutes each meeting giving my lesson. The members of my club have a huge range in skill (ranging from <600-2100). So what I'm wondering is, what should my 36 lessons be, assuming I want the lessons to be useful to most members?
Right now I have
1. The Rules
2. Basic Opening Principles
3. Basic Endgames
4. Forks, Pins, X-Rays