Should be able to pick some lead sheet up at the local big box home store. I used pieces that I cut from a scrap sheet that was in my hangar to get perfect balance on my RV-8 elevators. I added a nut plate on both elevators at the tooling hole just in case extra weight was needed.
Amazon also sells lead sheets and they are not very expensive.
When I hung and balanced mine getting ready for final assembly, I finally began to measure the out-of-balance in in-grams. That way I could better determine what weight was needed for the area I had to remove or add.
I have estimated that prime and paint will be 920 in-grams. Do you know what yours is in those units?
BTW - I cast a trapezoidal shape (made an aluminum form) equal to the 920 in-g and fastened it on the aft side for a perfect balance. Planning to remove it then tweak after paint.
Anybody out there just leave the weights as is until after painting? I haven't trimmed mine at all because of how the paint will change balance. This approach definitely leads to a strong amount of overbalance though.
McMaster Carr has stock of 93% pure lead and they are open on Sunday. Bought the 1/4 inch thick 6"x6" ( smallest in 1/4") so if your local you can drop by for some off the sheet.
Thanks Dpansier #2 post.