Do you mean the lower bracket that mounts to the engine block or the strap. There could be mixed terminology. At any rate, no I haven't. If you mean the engine block bracket, I've been trying to imagine if I flipped it what that would do to the generator lining up with the strap. It would lower the gen but it seems that it would swing at an arc that would be too low to match up with the strap. Plus, Donald had it the same as mine.
If you're talking about the adjusting strap, I really don't want to mess with that bolt that goes into the head. I've tried to loosen it with heat and penetrating oil and it won't move. But from what I've read, it might be best that I leave it alone.
However, even if I could loosen the strap to move up and down, I don't think it would make any difference in the generator moving any further. I think I'm gonna have to do with the advice to unbolt the gen from the engine block bracket and start again, only this time putting the belt around the pulley first and then re-bolting the gen to the bracket.