I bought the bolts from McMaster as well: http://www.mcmaster.com/#catalog/119/3094/=n89ir7. Note, these aren't torx head; but allen head. I used the M10 1.5 pitch with a 70mm length. Rather than spacers; I'm trying a block cut from a 2x4. The bolts fit perfectly and, so far, after a 4 hour road trip - passenger was a happy rider.