I don't think you are going to get anywhere near the tolerances you are expecting with that import grinder or a variant of it. What that machine is in essence a milling machine with grinding wheel for a head. Look at the base of the saddle and the over arm to the wheel head, they are dove tail slides with significant cantilever. Where as a boyar-schultz, Harig, or B&S Micro master, all have box ways to a surrounding column, and the table assembly has a large foot print so that the center of gravity to the working envelope is always within said foot print. The Micro master goes a step further with a traveling column instead of table and saddle. This is needed when holding sub tenths. Even if you got that Grizzly surface grinder hand scraped to perfection, I would imagine a few tenths of deflection at the out extremes of travel.
Who that surface grinder is meant for is creators who want a ground finish and milling machine tolerance. Things like knife blades, sheet metal punches and dies, and such.
Making milling fixtures that can be brought to the mill and treated as absolute perfect references, needs one of the aforementioned quality grinders. And I don't think you will find one for less that triple your budget, or the equivalent amount of labor.
I had my own saga with my Harig surface grinder. $500usd plus import from Vermont, and a few years of on and off work of re- scraping it. There is a lot more to hand scraping that just rubbing blue paint and scraping the iron. You need a reference that can be articulated to the working surface, and a means of checking overall alignment. At first I was using three marble slabs that had been lapped together to make one straight edge, and a pair of precision levels. I don’t recommend this method as I had been doing a fool’s errand much of the time trying to remove a twist. In the bed and saddle. The real break through was getting an 8- and 4-foot cast iron straight edge. Verifying them with the autocollimator, and checking for twist on a large granite plate. It was very much a pleasant surprise to have ground a 12in, 1in by 1in piece of cold role steel come to the granite and with about one ten thousandths arch over the granite and less than that in discrepancy with the micrometer along its length.
In those years I spent more time improving my machines that producing with them. For your desires, a new Chevalier or Kent surface grinder may be what you are after if the budget is not out of reach.
