If you want fields of 40, the only events you are going to see that are the SuperNationals and the Rotax Grand Nationals. 30 is a solid number for Rotax Challenge of the Americas, Florida Winter Tour, and the United States Pro Kart Series. Regional level, 20 is a good number for a field. Sometimes, I would prefer a solid group of 10 drivers to race against, if I know I have to be at my best to record a top result.
Motorsports cost money, as i am sure you have seen. Rotax, IAME, Rok, Shifter, Yamaha…it doesn’t matter what you pick, your going to spend money. You can race Rotax at a reasonable budget, you just have to do your homework, just like any other engine.
To please the masses, there really is no way to balance the performance of all these powerplants. It’s been tried for the last 15 years. Early on, it was simple. Now, with the advancement in technology, the tires, the chassis combinations, the consensus is multiple engine format does not work. Even Yamaha and KPV together was an issue, and they are both 100cc. It’s the nature of the beast.