Tony, that's awesome. I think an ideal multi use platen would be 6" x 22" with that pocket notch and a gap in the platen rubber top to drop the onesie snaps into.
We have 8", 10" and 12" sets on hand (having both 10" and 12" is a little redundant probably) and use the 8" for onesies but man, a 6" set like Tony's would be really nice to add to the quiver. Putting this on the to get/to make list.