The grip mount is cheap enough to try but you will upgrade pretty soon. I wouldn't skimp on the dot - get an Ultra-Dot 1 inch with their lifetime warranty ... they're about 120-130, buy once, cry once.
Astigmatism is an issue with vision correction and it can fool with the shape of the dot. When I shoot in evening matches I almost never see a round dot - more of an amoeba or comet with a pronounced tail. That's after 8-10 hours on a computer. Conversely, with early morning matches I get a clear, round dot. Eye fatigue + astigmatism is tough on precision shooting. I still work at irons for HP shooting and had an optometrist write a script for safety glasses with a point of focus at the front sight. As Magnumite suggested, I brought in the actual guns (if the eye doc is picky you can mount the dot or a set of irons on a block of wood that mimics the appropriate grip and eye-front sight distance) and worked from those measurements.
The target can be left blurry but, as you noted, not too blurry. It can take a few trips to the doc to get it straightened out. I used a bunch of the cheap Walgreen's reading glasses to get close but the script safety glasses have the advantage of allowing a different lens in the off eye so I can actually use my scope. If you don't now, you should also practice with both eyes open... makes quite a difference in eye fatigue over the course of a match. I still need to use one of the flip-down white blinders to partially obscure the image in the off-eye ... for rifle shooting where the flip blinder is in the way, I just put a layer of opaque scotch tape over the top half of the off eye lens.
Just more to think about ...
/B