So, today I had a chance to do the air filter, and grabbed those photos. This is where I mounted the Rostra Cruise control box a few years ago when I put it in. I'm using the bracket that was originally used for the grip heater connections. Those are now located further to the right.
DeanB had also asked about where I attached the cruise cable itself.
Here's a close-up of the peg that I drilled. It appears to be a stop on the throttle cam that is meant to "catch" the cruise cam on full wings. In our case, the outer floating cruise cam is not present. I simply drilled this peg with a ~1/6" hole, slid the provided Rostra end onto the peg, then put a cotter pin through the new hole to hold it in place. I still think that using a full wing throttle body, which has the cruise cam on it already, is the preferred method, but this seems to work just fine.