Stacking spacers comes VERY highly unrecommended around here. Those who know much more than me say it is very dangerous. Not sure if you are 2wd or 4wd. If your 2wd you could easily get that lift with some spindles and some RadFlo coils for a fairly good price. If our 4wd you could get some new UCAs and some RadFlo coils and get about 3" of lift maybe a bit more if your will deal with a bit harsher ride from the higher preload. I definitely would advise against your current plan of stacking spacers even if it is cheaper.