George, I have been on my SS/ST with the standard foils, bat wing rear and bat front/back.
I have also spent time on a LEX.
I like the Bat rear on the standard ski. It skids better, jumps a bit better and is a bit more forgiving on landings.
With both bat front and rear, it rides very very nice. Skids like there is no tomorrow, lands in a skidder if you land a bit back, very fast reacting.
This weekend, I will try a LE front and Bat rear on my ski then decide what to buy/do. I would like to try a LEX with Bat front and rear just to ride the lighter/taller ski.
My buddies LEX rides realy bad with the bat rear, but he has the older LEX strut and would need to machine the rear to work with the added lift of the bat wing rear.
My ST did not need the rear adjusted/shimmed. If anything, it all most has to much lift. It gets a bit tiring to ride it from pushing down on my feet all of the time. I have shimmed some lift out of the rear when feeling lazy.
I'd say do the bat rear, but the change is not huge. The bat front and bat is very nice.