I have a few on my fish , and made a tool to use for them.
Did u notice the fairly tite hole he had drilled ? Imperative to fit tite , the titer the better.
He also was using ''aluminum'' nutserts , much easier than steel nutserts !
I even put my front engine bay strut bars in w/ them , but their tied in , in 4 places , instead of three as usually done .