For the missing bolt, I use the following method. Use an allen head bolt, drill a larger hole in the mount part way so the head of the allen bolt is counter-sunk into the mount.

For the throttle- use the ball link for the throttle arm. I use a piano wire often for throttle. Drill a hole for the wire to exit firewall and miss tank and mount. Have the end go past the carb a ways. Now bend a u shape into the wire bringing the ball end back toward the throttle.

Hope that made sense.