Here is another angle on the mirror problem. I bought stick-on dome mirrors from an auto parts store, peeled off the sticky pad and cut two parallel slots in the back.
I thread through the buckle-type of my watch, positioning the mirror in such a way that I can see my fuel tank and its contents and I also use the mirror to look back for airplanes. All the time, my hand is in normal position on the brakes.
It helps to put a little paint/ varnish on the back of the mirror to keep your band from wearing away the reflective surface of the back of the mirror.
I tried two and four inch sizes and the four inch works very well.
The mirror is very easy to adapt (see the pictures below)