I posted the same question back in May. I ended up purchasing an assortment of very small metric taps. Had no sucess, as the threads were tapped from the band side of the lug, and it is very difficult to start to chase the thread from the finish side, as mine were buggered up from the shop drilling the lug part way for the screw head recess. by mistake. I could get it started in the good lug side, no problem. If your threads are messed up on the band side of the lug you may be OK. I ordered the taps from Micro Tools, I also posted a link to the in a previous post. I'll see if I can find the taps in my box and then give you the size that worked.
JR