dont worry mate! it happens to me too im gettin roughly 38-40" sidehopping,one day i can do it the next i cant.what i do to stop this is focus on the top of the wall! hope i helped. beeeenjiiiiiii! XD
Magura hs33 and louise,and any other hydraulic brake are good if you can keep them working well.But if your like me and cant i have wo avid bb5's and the work a treat and are the easiest thing in the world to repair .
Sometimes hairspray does not work very well as it sometimes stays slippy. However on foam grips maybe use some double sided tape worked on my last trials bike. Hope i helped .