Here I go again needing some knowledge from the 'old dawgs' ;)
The Patrol is the first leaf sprung truck for me and in order to clear 35x12.5's without a bodylift I want to go with a set of custom fabbed shackles. Hyper shackles for the rear is already decided. How do they behave in the front ? Are they driveable or is it a PITA to drive on the street ? Anyone tried them ? I need flex and don't want to invest in new springs now.

http://www.offroad-events.org/Saverne5.JPG

See why I need flex ?

I haven't driven a dual shackle rig before, but I've heard it isn't too bad even up front.

You can always pin the upper shackle while on the road to prevent it from opening up. You may also want to consider putting a panhard bar up front to keep the front end from moving side to side.

they dont work very well. but if you want some lift do a spring-over, it should net you about 4" of lift and flex a hole lot better with the stock springs.