Acouple of interesting points......

While doing some pistol bullets today, I found that I got much better, almost perfect, coverage with Harbor Freight red by using a lot less powder and just shaking a few moments more. I was using about two teaspoons of powder I now use just one. Also, if you take the no stick foil and crumple it up and then carefully unfold it, it makes an "alligator skin" type surface you can lay the bullets on their side and don't have to stand them up. This left no marks or bare spots on my bullets and they don't roll around. Be careful not to let them touch each other though. Faster too. It keeps getting easier!

I'll have to try that with my rifle boolits.

Found that out awhile back and posted it, but it has been a long while back. I have done it with less just 1tsp.

I use a Lee powder dipper. I think it translates to 1/2 teaspoon. I never put more than 2 scoops in (1 full teaspoon) but I have not had the problem the OP wrote about.

When I have more powder than needed its just visible in the bottom of the bowl. I am learning how much to use by what's left after I tumble. ;)

Motor

When you lay the boolits on their sides don't they end up w/ an uncoated stripe on them?