Steve
No matter how many boxes I install, the part I always fuss about the most is steering box placement.
Think this thru. Are you otherwise DONE with this? Wendell at over the hill made me some hi-steer arms, and I can tell you hi-steer is a huge factor in setting up steering geometry. Are you sure all aspects of your lift are final? I have 5" of lift on my 45, and that was also a factor in setting my gearbox for and aft, as well as pitch.
In the end I ended up taking the plate that I offer and trimming it to rotate 1/8" to fit my exact needs. My steering turned out 100% bitchin.