Hi Shawn,
Just watched your video, and yes it sucks when what should be fun is interrupted by a significant unexpected repair, with uncertainty, delays and cost. But most of us have encountered that at some point--a dismasting, grounding requiring a dropped keel to check for damage, blisters, collision requiring fibreglass repairs, etc. Most of us have been tempted to sell the boat, take up golf or similar. But if you can problem solve through this repair and get the help and friendly assistance you need, you'll be able to sail again and this will become a distant memory and good story to tell over drinks.
It's hard to know when to try to do it yourself, or when to hire help, but your decision process in your video seems sound. Would the rudder maker(Foss?) be able to tell you how much buoyancy, how hard it would be to install in the water, especially if you could hire a diver to help you?
Keep your spirits up you'll get it resolved!!
Frank