OK, that photo shows some detail the other one didn't. Now that we've resolved that, I've got another suggestion. Rather than modifying the studs, how about fabricating a spacer plate to fit between the brake drum and the wheel? A piece of steel plate about 1/4" or 3/8" thick the diameter of the wheel mounting surface with the proper lug bolt holes drilled in it should space the wheel out far enough for the inner nut to tighten properly, and the slight increase in track width won't make a noticeable difference. The spacer could even be attached to the drum with a couple of flat head screws, maybe 5/16" or 3/8" in diameter to keep it from coming adrift during wheel changes.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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