With a 2" coil spacer, I had to just about max out a set of double-eccentric alignment cams (4°?) to get my camber back to 0°. I'd imagine that about 2 1/2" is about the limit while still maintaining acceptable camber/caster, using readily available alignment cams. That being said, I have seen a few guys stuff 4" lift coils in their E-vans, but I wouldn't recommend that.
Typically 1.5 maybe 2" if your lucky and you will most likely need to clearance you I-beam so your spindle doesn't rub. This will also steal most of your caster.
This is a lot cheaper option then the Ocotillo Cruiser lift which would be your best bet if the price is in your budget. https://weldtecdesigns.com/product/1...tillo-cruiser/
Let me know if you have additional questions.