Limiting tyre choice by either compound or number actually restricts the lower-order drivers more than the top guys. Limited numbers means that you will always be at a disadvantage on those tracks where worn tyres give less performance - lower-order drivers find themselves less able to control the car and the fun factor disappears. Limiting compound has the same effect - if you're not hot on the set-ups, or can't control a car well, then driving becomes a chore, not a joy.
Level playing field - no such thing. In the last 35 years, it's been tried so many times, but it has never worked. Many of today's top drivers learnt their trade when there were no limits on tyres, and they had to pay for their huge box of tyres before their skill attracted the sponsorship they have today.
No one is denying that cost needs to be controlled as best it can in order that more people can stay in, or join, our sport. Nonetheless, other classes look down with envy at the low costs of Off-Road compared to the On-Road classes. I wish you luck, but I don't think you will find that limiting the number of tyres used will make more than a passing difference to the cost of your class, but it might well have a huge impact on the fun people get from driving their cars when they can't have the best tyres for the meeting, and have to drive a poor-handling car around for heat after heat.
