Stoney,
I took a piece of 8 X 16, 1/2 inch plate and notched it to clear my grindstones (call it 1/8" clearance). I made it pivot such that when the plate is "level," the top of the plate is radial (square) to my (8 inch) stones. The plate is positioned such that it is tangent to my stones at the upper limit of the pivot. The pivot itself has 1/2 inch shoulder screws for the axle and I made "sleeves" for them such that when they are tight, the table is locked in position. I milled the outside edge straight and dialed that in to the grinder's spindle. I mounted a (round-bar) linear bearing set below the table so I can add "attachments" and have them travel parallel to the grinder's spindle.
When I am working "offhand" on my grinder, I have a full-width table to base things on. I have miter gages that travels on the linear bearing set for work of that precision. My miter gage set includes: standard pivot miter gage for rectangular work, vee-block miter gage for round work, and an "adjustable feed" gage cobbled together out of an old (on/off) magnetic base for feeding small pieces into the grinder. Because of the geometry (and two "hinges" in the positioning of the various gages), I can just "swing" my parts towards me to dip them in my "dunk pan" (an old bread pan that sits within reach on my stand) to cool them off. The linear bearing bushings for each of my "gages" has been slotted and relieved such that I can lock it in any given (width-wise) position with a thumbscrew.
I don't use my "gages" anywhere near as much as I thought when I built this unit. (I tend to do such work on my toolbit grinder flat-face set-up.) The mag-base "gage" (faced with UHMW where it contacts the table) gets used more both of the other "gages" combined and may be the neatest feature of this approach. I would probably use the gages more on this were it not for the fact that I have had a toolbit grinder mounted on the other end of my "grinder bench."