I'm afraid this is an issue across any and every league form all organisers. 10 weeks is a long period of time, sometimes things come up out of people's control and others just lose interest because they may not be competitive or in title contention, or they just stop enjoying the game.
If you are serious about setting this up, my first advise would be to organise a social event to this format. This tests out interest as well as the car, tracks, format, settings etc. you've created, and enables you to make any necessary adjustments.
If, after a couple of social...
Hi Benjamin and welcome to AOR!
If you sign-up for our F1 league, you will be asked to complete a Time Trial. Using your time from this, the league co-ordinators will decide on which tier you should be racing in. This ensures close racing for everyone. You will then be added (mid-season sadly)...
A quick thing about lengthening Endurance races. For some people who live in Eastern Europe this would mean staying up until past midnight. With work the following day, this would be impossible to commit to.