I'm a disabled guy so I already type pretty slow. I hope I can slow down enough more you can read this.
A '53 3-speed should not need to be double-clutched. You should have synchros for every shift except into 1st or reverse. I'd start by checking the lubricant in the transmission. First does it have any, and assuming it does, is it clean?
If the lube is okay I'll have to let someone else take the lead on your questions because I know little about transmissions.
