During the development I have experimented with the kickup. Having a few degrees is a good thing for off-power stability, for on-power I didn't find the differences very pronounced (although that was of course on a prototype). I didn't try posi-squat; it could work well on-power but I do expect a considerable negative effect off-power. No harm in trying I guess, if you have a LRC and HRC hanger?
For reducing side-bite up front, 4WD tires can help. When using wide/rear tires, have you tried the following?
- Moulded inserts. Reduces deformation & twisting of the carcass; I find the grip more consistent, the feel sharper and more confidence inspiring.
- Cutting multiple outer rows of spikes. Reduces sideways bite, particularly at speed, without the cost of sharpness and steering in slower sections.
- Applying glue on the outer wall of the tire. Similarly to removing spikes, it reduces sideways bite. In case of soft compound tires it may also stiffen up the outer wall of the carcass somewhat.
- Widen the car to 250mm. It's not an actual change to the tires, but the room to play with this varies from tire to tire. With the Asso 12mm hex I run up front I can use a 1.5mm shim between hex and rim on each side with most tires (including Schumacher MiniSpikes).
- Check the rear bite. I find that on medium-high bite, having enough rear bite is crucial. If the rear end lacks grip, it may slide out, making the car hook. Sooner or later the rear picks up grip again, at which point the sideways forces become so big that the car simply grip rolls. I always use 4WD tires on the rear in combination with (very) soft inserts, so the car can utilize the 4WD tread and flex in the carcass to generate grip. For the rear it also makes sense to widen it as far as possible within the regulations in order to maximize stability.