Suspension & Brakes - simple question, best way to install STB?

Hey, I purchased a STB off of a seller on eBay. He constructs them himself, seems like the product is good quality. No instructions were included with the brace so I have a few questions regarding installation. First, my concern was about installing it and causing the paint on the strut tower to scratch since metal will be rubbing on metal. I was thinking about cutting out one of those paper thin gaskets to put between the body and the STB this way scratches won’t occur. Second, how tightly do I tighten the brace? Thanks for the help!

If you want to make gaskets, thats fine. But I dont have any scrating from my brace, once its tightened down, it doesn't rub. Torque the nuts to ~30 ft lbs.