I put together a frame nailing jig (deep) from the plans here. Took great pains to cut precisely to size. Tested it with a couple of new frames, found that it is just a hair long and the bottom strips will not nail up in the jig.

I think I can easily remedy this either by shaving the spacer bars on the side of the jig or by rabbeting the end boards by perhaps a sixteenth.

Anyone have any experience here? Are commercial frames from different suppliers sometimes a hair different in length? If so, I will want to make the jig adjustable.
Rabbeting the end boards is easy as both sides & both ends can be rebated to fit 4 different brands of frame.

Any tips? I've always done this the hard way.