Is the size of the ground glass on the spring back the same size as the ground glass that is in the removaled focus panel for Graflok backs? I have a Satin Snow GG in my Anny's spring back right now, and am upgrading it to Graflok. If I can save a few bucks by persuing a Graflok with missing or cracked glass, and just use the Satin Snow, that would be great, but I'm not sure if the dimensions are the same, or close enough.

Anyone know?

Probably would fit, but I don't think you'll save much anyway, since you need the back, and the focussing panel. You don't have to have the shade hood of course but it does protect the GG screen. Lately there have been a bunch of backs, panels and hoods listed separately and complete on the auctions site, so prices have been more reasonable to pick up these items. So you might do well to keep an eye on some of the listings and see if you can't pick something up.
The only thing I can add is that if you don't have a fresnel screen on your current focus panel, you'll probably get that set up on the panel that comes with a Grafloc back as they are hard to find without the panel milled out to accept the Ektalite fresnel. I finally found a grafloc focus panel without the fresnel milling. I don't like the fresnels very much. I find the black lines they cause distracting with an 8 or 10X loupe. I also prefer fine focussing with original Graflex GG but I have Satin's glass in a couple of my cameras and keep a couple on the shelf for replacements. Both are good, Satin Snow a little brighter I think, while I find the original a little finer (based on graflex screens from the mid-forties onwards).

I got one coming with glass. So, if the SS doesn't fit, I won't be sitting without glass.

Quality doesn't matter much to me at this point. I'm hopeing to buy a Shen-Hao for all my tri-pod/ground glass work soon, and optimizing the Speed Graphic for handheld/rangefinder usage. So I'll probably only put the GG on every couple of months to make sure that the rangefinder stays accurate.