whether cranking the stock TB's or getting new ones, you are only going to get a max of 2in lift in the front. Main problem is that you are going to be sitting on the bumpstops after cranking. Most of us trim the bumpstop(cut in half)to compensate. OME springs are supposed to give you 1.5in (I actually just bought the softer ones myself but have not yet put them on) and I think the Toyota shackels, if you got the stock ones, add about .5in lift. The stiffer OME rear springs are to be used if you are hauling an extra 500lb consistently or towing (according to ARB website)IIRC.
For the stock TB's, it's possible one is maxed out because it was removed and not put back correctly. You might try removing them and re-index them or set them up with stock specs. Look up how to do it on here because you want to make sure and do it correctly (for safety reasons). Hope this helps.