Something that really would discourage me is having to do 5 x 5 laps; 25 laps, with realistically a couple of minutes in between each race - It's a bit heavy for me, and I'm someone who has more time than a lot of others.
I know from experience that 5 x 5 laps really isn't that onerous. Unlike the large grid races, there shouldn't be a lot of waiting around to organize everyone. It shouldn't take much more than 1 hour. What
IS onerous, IMO, is having to spend 5 or 6 hours practicing in advance, in order to be remotely competitive. That's what I'm trying to avoid.
I think everything suggested above has its pros & cons. However, this is what I think we should go with:
Participants agree to a time to meet online.
At that time:
Challenger suggests 5 cars. Challengee picks 1.
Challenger picks 3 tracks. Challengee picks 2.
5 laps per track (can be more if they both agree).
No assists allowed (except automatic). No tuning allowed (random liveries).
Participants have the option,
if they both agree, of 10 - 20 minutes to dial-in chosen car before racing.
I really think this is the best idea. The Challenger has the advantage of knowing which 5 cars
might be used & also of the 3 tracks he will pick, but that leaves a daunting amount of potential advance "training", especially as he does not know the other 2 tracks that will be used.
The idea is to simulate a scenario where you turn up at a track(s) you know well & are given a random supercar to race. You don't know the precise braking points for that car & are forced to wrestle the beast on-the-fly, by
feel, around the track. Sound like fun?
I really hope people will take this in the spirit in which it was intended. There are no "points", so losing a series is of no ultimate significance - you will always have the opportunity to make up your position later. The idea is to get the chance to race a variety of cars & tracks without a lot of prior practice, making the racing a little more spontaneous &, I feel, true to RL.
My suggestion would be to run the League over the course of the (Northern!) summer, or until GT5 finally shows up, & then run a final larger grid race - perhaps the top 6 - to satisfy those with a craving for world dominance.
,weapons...errr...Cars and tracks to be arranged on the fly right?
In fact, if we work together and are clever about this, we can go quite far. If you challenge me 3 times and throw the race each time, I can shoot right to the top of the ladder. 👍 It's brilliant!
I wasn't suggesting Hun would throw the race.....on purpose. 
