Front vs Back Standards for 4x5 Toyo G 4x5. (How are they different?)

Are there any Toyo G 4x5 users out there . . . ?

How are the front and back standards on a Toyo 4x5 G different? If only marginally different, can one use a front on the rear? I see multiple fronts for sale on EBay, but no rears.

Yes, in a pinch you can use either in front or in back.
The difference is one sits slightly forward on its base, the other sits slightly back of its base.
Also, some front standards may or may not have the fine focusing meant to be on the rear standard.
Buy a second front standard, use it just to be able to use your camera; meantime look for a proper rear standard.
When ou find one, you'll then have a spare standard you can use for parts or a macro set-up.