The first time I mounted MiniMotos was on my QB.
The first hard stop I had to make with them (oncoming car didn't see me and turned in front of me) I pulled too hard and went over the handlebars, fortunately only spraining my elbow. I missed the car altogether though, came up short (they stopped). I was immediately sold. Went on to buy some Motolites for a mountain bike.
As for clearance, you have plenty of room with those 42s.
Currently, I have the pair of MiniMotos split between two bikes, on the forks of each. Paul Touring cantis / Neo Retros on each rear. Like Bones.
But I did have them on the rear briefly. I did not use the brake cable stop on the frame, just went around it. That bridge felt a little sad unused. One could perhaps mount a light there...
Have fun
Patch, NYC