Joe,
Inserts on the wheels are set up for 3/8 already. I do not want to swap out to 7/16 and get wheels and hubs redrilled to fit 7/16. Not comfortable with present 1.5" stud length and having less than 1/2" of stud left sticking out of the rim after mounting the wheel. Fronts I have a little more meat available up there. Studs IIRC are threaded almost all of the way. Wheels are 8 Spoke JBW, similar to Minilite or VTO. Wheel thickness in the hub area is perhaps 3/4" vs. Pressed Steel wheel thickness of perhaps 1/4" probably less for both measurements but Aluminum wheel is thicker hence the need for longer wheel studs. Since I have not measured this difference in thickness already just guessing on actual thickness.
Being able to replace studs without pulling everything apart would be nice but I don't think possible.