Best thing to do is measure the distance that would make the coil, replacement or added spacer, work with the already rear lift. I'd measure the static height of the coil, then lift the front frame enough to 'even' the truck level. Remeasure once again at the coil the extension necessary. It's not scientific, but RDC (real damn close). This is the necessary height needed. Adding a spacer is the simplest, or replacing the coil is easier, however, you do have to determine the amount of spring capacity is necessary (meaning static load height of coil, number of coils, spring rate, and sprung-weight up front. Do you have the measurements of the stock rear spring for comparison to the ZJ spring?
As for the strut configuration, you should notice that there is not much droop travel. What others have done is to flip the cone mount. Take a look at Calmini's mount with their 3" lift on Izook.com. This should give you an idea of how much you need to lower the top mount for additional travel, both up and down.
Lastly about that cv shaft, both of my front axle shafts on my XL7, are offset to the back by at least 1.5" centerline.
