The engine is back in the Cobra and I've had numerous opportunities to use the new starter under various conditions. It's worked flawlessly. The solenoid location is infinitely variable and I rotated it around behind the starter body away from the heat of the headers. When it's started after a hot soak, it spins just like when it was cold. The only time it struggled was when I was experimenting with spark timing and got it a bit too far advanced. Right now I'm running 24 degrees initial advance, which is up from 16 that most recommend, and the starter seems to spin the motor with ease. Based on the detailed analysis that Robb did, working with me on identifying the potential sources of mismatch between the starter pinion and the flywheel ring gear, I'm totally confident that I won't have any more broken teeth on the flywheel. The RobbMc starter is a quality piece that functions very well. If you can make a stock Ford starter fit in your application, it should work fine as well, but if, like most of us, you have space constraints for starter installation, I can't recommend Robb's starter any higher.
I've attached a picture of the starter installed on the engine.
Chuck