1/2 Plate Insert for 5x7 Plate Holder

UPDATE: The original version did not work with my box of J Lane 1/2 plate Speed Plates. There appears to be a mismatch in dimensions somewhere. I had to make the space for the plates wider, but then there wasn't enough overlap to support the sides enough. So I have changed this to ONLY support the plates at the two ends. This has now been tested successfully and will fit the holder, allows the back to close, and is light tight. This new version is uploaded here as v3...

This is an insert for the very nice 5x7 dry plate holders posted by robertbieber. This SHOULD let you put a 1/2 plate (4.5x6.6.5) J Lane Speed Plate in the 5x7 holder. I have not yet tried to insert a plate, though, I have only test fit the insert and it seems like it will work.