The issue with mounting it there is that you'll find on certain props that it gets hung up, especially in narrow ports or something where you have to get the left side of the rifle jammed up against a horizontal surface.
I've run red dots on all my precision rifles for a few years now and it definitely gets you on target faster. I mount them at about the 1:30 on a ring cap. My justification for doing so is that you keep the lowest possible profile (vs a 12:00 mount which makes your scope "taller"). I don't cant the rifle to get behind the red dot though. I keep the primary optic plumb, dial on my 600ish yard dope (for most short action calibers) aim at a target at 600ish yards and then co-align the red dot to the primary optic's reticle. In that way, if I put the dot on the target between about 200-1200 the target will be in the FOV of the primary optic when I drop down behind it. That being said, I generally shoot around 13x for positional and maybe 16x prone (unless zeroing or shooting at a really tiny target) as I find the added FOV helpful to not "tunnel" on target as well as for self-spotting trace.