Main halyard uses a aussie ring and therefore no need to cleat. Just coil and stow extra halyard in trampoline bag pocket.
I have two pivot swivel cleats like your 141 and 299 but Spring brand mounted on the mast below the boom. The upper one I use for the cunningham. The lower one has metal teeth within carbon block and no eye strap, I believe this would be for the spinnaker and I will review next time mast is up.
I believe my sheets are 7/16".
I would not mount cleats. you can always attach bungie to end to sheet to keep in place. If you have the main sheet in hand you technically have the main sheet in hand. If needed I have crew help keep separated or hold that end of the sheet.
I have a trampoline bag that is the coolest thing. It is 6'x2' and is a mesh bag. One of the two outside 2'x2' big pockets hold 4 trapeze harnesses for triple trap and the other holds 3-4 wetsuits. The other 2'x2' inside areas one side has two pouches and the other has three even sized pockets. These hold main halyard, jibhalyard, camera, tools, bow line, extra righting line, righting bag, gloves and maps. It has very easy access, I also place a throw cushion underneath.
I place long term storage in the hulls and try to not access oftten while under sail.
I need to talk with you about your righting pole.