Rear Caster? Is he driving a Pallet Jack? Last time I checked caster was a function of steering wheels. and the kingpin Inclination can effect dynamic camber, however last time i checked we were dealing with the rear of the car. Go on ebay Pay $30-50 and buy yourself a Pyrometer. find out where the tire is getting hot,

center= your pressures are high and lowering them will give you more grip,
edges= your pressure is low and you need more pressure for optimum grip
outside edge only= you could use more Negative camber
inside edge only = you have too much Negative camber

Every suspension setting is adjustable, in any car, (it's just how hard you have to work to acheive it) in a honda there are a huge amount of parts availble to get whatever you want, shims, camber links etc. the most important thing is to LEARN what YOU need to get the biggest flattest contact patch on the road, you are doing the right thing by running as many events as possable, driver is more important then any part, and you will be able to know what settings work best for YOUR driving style.

my other worry point is with worn stock shocks in the rear of the car the tires might not be following the pavement as they should, this would cause the car to become unsettled in the rear but not in a predictable fashon, and a stock shock will NEVER have adaquate rebound damping for a "Race" spring.

most importantly anyone that tells you PROPER pressures to run is blowing smoke up your A$$. Pressures will vary from car to car, shock to shock, day to day, and By driving style. Sure you can get close with a suggestion but no two cars or drivers are identical so the only way is proper testing and quantitive data, Then you can start logging pressures on your own.

Jeff