Thought I'd share the DIY cuddy cover that my daughter and I recently made. I followed the basic instructions in a video by Sailrite showing how to make a companionway cover, though with some minor "adaptations" (aka mistakes). I'm very pleased with it, though no one will accuse me of having paid a professional to make a custom cover. I wish it had come out a little more taut. I chalk that up to installing the snaps in an iterative way and not taking advantage of the snaprite system from Sailrite. When this one wears out I'll do it right.
The fabric is Sunbrella "Odyssey Brown." I could only purchase it online, which meant I could not be sure it would match the brown in my 1984 original "Earth Tone" mainsail. It came out pretty good - same basic hue of brown but a little lighter than the brown in the sail.
I thought about adding a mesh pouch to it to serve as a rope bag for halyards, but realized (a)that's another complexity and (b)I can just undo a snap on the top and drop the excess halyard into the cuddy.
I used marine silicone caulk on all the screws into the bulkhead.