As I understand it the HRC is used to correct the roll centre when using lower ride heights. Frank suggested I use the HRC, +3 rear hubs and Diff for a 20/21mm ride height as a starting point if that helps.
The above is for grass and bumpy astro, I think the HRC is really useful as it is allowing me to use the soft (kit) springs without getting lots lean. I have also tried stiffer springs and found they don't provide the same improvement compared with my previous car (DEX210).