I own a can of Krylon white primer. They make at least two different "COLORmaxx" gray primers one darker than the other. Very confusing. Do you remember what you used? Or maybe you had enough topcoats of the Camo Olive that it didn't make a lot of difference...
Edit: This primer would probably be good enough:
https://www.walmart.com/ip/Krylon-51...01318/19289963
That almost clears up matching the Panzer III, Sherman 76, and the late Tiger 1 except possibly getting the brownish stripe color for the last. Anyone have any thoughts on the T-34 Soviet Green? Thanks for all of the help again.