The thread on sleeve style studs are basically long bolts threaded full length that the sleeve then screws over, locking the bolt and providing the proper wear surface for the wheel. I have used them, but avoid them now. Mostly because they are a PIA to use as opposed to a true machined double ended stud. Most aftermarket flat seat race wheels have 11/16" holes. I've had to lightly hone wheels in the past when using the sleeve style.

If you insist on using 1/2" studs, at least use decent, US made parts. I've seen studs made from Chineseium that broke and really shouldn't have.

If the results don't match the theory, change the theory.