whats the rules of thumb regarding positive and negative chambers and the recommended pressures on the fork leg????

ta

RS Recommended pressures are usually on the high side. Start at the lower end of the range and set about 20-25% sag from there.

Always set the pressures be letting out the -ve, setting the +ve, then resetting the -ve. This stops the fork being dragged down.

Setting more -ve can be a bit of a waste, because all that happens is that you loose a bit of travel and the presures equalize anyway.

Keep both pressures the same, or maybe 5-10psi LESS -ve which will give a more progressive feel and stop the fork diving, if you find that happens