using tubes as wheel spacers?

NHRA bans spacers for a reason. Most of them are made from aluminum. Your idea of using studs as spacers is an even worse idea. I saw a guy with a gorgeous 62 Corvette watch his slick finish the 1/4 mile ahead of his car. Not to mention the damage done to the body when that slick exited stage right. In a phrase, "Don't even think about it!" Get wheels with the correct backspacing.