I quit using bolts, now I just buy allen set screws the length I need I can get them up to 3 or 4 in long. Screw them in the head and use a nut to pull the rocker shaft down straight.
That's a really good idea for hold downs, do you have to use a jam nut to keep them from backing off any? I've come to the conclusion that Fastenal is pretty much just Hobby Lobby for men...
