6" lift plus 1.5" spacer
I dont know that ive ever seen a zone lift. I can tell you ive heard to stear clear of stacking spacers. So if your lift uses a spacer in the front id say you might not want to. There are fellas that do this though. Im sure they will get you lined out more then I. You should post this in the suspension area, if you havent already.
It seems that most guys try not to go over 2" . Ive been checkin this out for a while also. Again im not a lift expert i have just been reading up on this for myself. Ive ran a few trucks with leveling kits and yours should look the same if your angles look stock-ish now. Ive ran them for 50k+ miles with no problems for me. However with heavier wheels and tires im sure it will increase wear and tear, but thats the nature of the beast. Plenty of fellas here doing what you suggested and are ok.
If you have 6" lift spacers then I would suggest not stacking. But if you running coilovers then yea you can. I ran a spacer on my ranch with my 07.
You should be good with a 1.5", angles will be steep but ok
You should be good with a 1.5", angles will be steep but ok


