I have a limited experience with bags, but in order to limit body lean you must have an isolated 4 bag system. Each bag must be check valved separately.
If not, the body roll will squeeze the air out of the outside bag and transfer it to the inside bag, increasing the body roll even more. (remember old air shocks hooked with a T ?)
Lowering can be also be accomplished with adjustable coil overs, adjustable spring pockets, shorter custom lowering springs (coils or leaves), leaf spring lowering blocks, or cutting the coils off your existing springs. It depends what system you have already, front and rear.