They actually do make this size. They have to be ordered or you have to what I did. My auto has the same size restriction. I have several 23x28 screens and found some 18x20 screens. Those are ID so 21x23 so I took top and bottom and made my own. Was able to pick up the 18x20 for $7ea. After doing all that I discovered that I could use the 23x26 screens fit by moving screen clamp as my press have front and rear clamps.I want to buy a Diamondback C in 2018 so I’ve been watching for some used items I know I’ll need with a new automatic like a stretching table.
I see one used for sale so I looked at the Diamondback specs to see if it will work, the max frame sizes is 21”x28”. I’ve never seen this size in Neman frames, can I not use retesionable frames with the C?