you really cant go wrong with tsls..
if you goto 38s would you not be lowering the truck a few inches? (you mentioned that earlier) or is a fender chop in store? what are your plans to get more flex out of the front, i think you also said you wanted to do that?
also you said you wanna goto a 16" rim? as far as used tires go i ALWAYS see everything in 15s in my area, and tires are EXPENSIVE new, i bought my 33" procomp mts new and for how long they lasted, i'm going used from now on!
if it were me i'd probably stick with 36s, lower it a bit, work on the flex and chop (cleany! is still a nice body) the fenders and bumpstop if need be. you're putting a bunch of money into new chromo axles, you should just stick with the 36s and have a bulletproof rig that dosent snap axles every trip (wish i didnt snap axles all the time).. and maybe you can throw the doubler back in
but yea this is coming from a kid with all bolt on mods, so i'm sure you know what you're doing much better than i