Finally found M6 40mm screws - had to buy a bag of 50!
Got it mounted (pics cometh).
On the drilled side, I was kinda close to the engine mounting bolt. There's not a lot of room behind the bracket for using your fingers, but you can get to it. I put a lock nut on with blue loc-tite.
On the undrilled side, I just screwed in the bolt and used loc-tite.
I used loc-tite on all of the small bolts that mount the spike to the mounting bracket.
All that's left is the chin fairing and chrome wheels, and I might call it done... (unless I can find a sleek front fairing like they were going to put on the L&M bagger...)