endurance race...need input

[x.system]

Hey guys, me and a buddy have been given the task of setting up an endurance race at the end of our tt season. We will be using the same tt track for this race.
I need to know from you guys that have ran these what works best, the number of laps or a time frame. We have discussed briefly a 50 lap race but that seems short to me. I'm pretty sure we could do 50 laps within 20 to 25 minutes on this course.
We want this to be a team event and are planning on a huge payback plus trophys. Our only limits seem to be fuel right now. We run both 2 and 4 strokes at the same time so I don't want the 2 strokes to have to stop for fuel when the 4 strokes won't have to.
Right now we usually have at least 10 quads that show up but we want to get at least 20 quads so I will be advertising it on various sites.
What do you guys think about winner take all? or should we have 1st through 3rd or 5th? Winner take all would probably be about $500 for the winning team.
If you have raced one of these races I need your input.

[MTS]

go 6 hour race

[slothminx]

you could have that you have to have at least one stop in the race this should help the 2 strokes

[NOS_350X]

Let them have pits, and have them non times, with a time limit the pit can last. example, have somone timing the pit times with a 2 minute max, keep track of it example
#84 -1 minute 34 seconds

subtract the total pit times for there total race time. just limit the number of pits, and how long they can be. Anything over your maximum time goes agenst them.

[RideRed250R]

hmmm..... i say you need to get on the track with a trx250R with a full tank and run it, till it DIES i mean all gas is gone, then take that number and use that, i say 155 laps with no fuel pits, thats a good number
adam