Hi, sorry for the late reply.
I did not look very hard for different wheels as I figured I could always do that after its complete. I also was not sure what the front and rear fenders would look like. I still need to do something in the rear. I do not think there is an immediate limiting factor, I can measure when I get back in town but I seem to remember there was enough room for another 3/4". I think the brake bleeder and caliper hose line are close but a 17 or 18 might solve those problems. I guess at some point you lose turning radius and it will start rubbing. My buddy says that the fj cruisers stock wheels might be a good option.
Also the amount that the tires stick out past the body is different on the passenger side vs driver and its opposite in the front, I am trying to figure out if I am supposed to get the adjustable panhards to even them out a bit or is this how it is designed to work and I should leave it as is.
Are you doing an Aqulu tub or adding on to a stock 40 tub? please post your thread if you have one