Well, i don't think the LE's should be the cause of the taz and slot problems.
My version is with p90/100 LE's and isn't that stiff either. Still it does the tricks fine.
Are the positions of the apa's accurate?
You have to take in account that SUL tricking is a bit different from tricking with a STD version. The inputs can be different and slack management is very important. Also guiding the kite through the rotations.
Do you have a picture of your kite?