I have had a few repairs made to the hood on my O'Day 222. The first one was to the trailing corner that developed a crack. I had a local welder attach an aluminum patch to both corners. That was about 4 years ago and it has held up fine.
Then last year, I found quite a few stress cracks and so I riveted in aluminum plates (with the help of a friend with a lot of great tools) to the forward and trailing edges of the hood. The forward edge required some careful fabrication since the curve of the rudder cuts in. The repair has generally worked pretty well and it definitely eliminated the shifting of the rudder vertically as a result of elongated holes where the rudder stops against the bolt when in the rudder down position, and where the pintles attached to the hood. The fix has probably bought me a few more years without complete replacement.
If I do have to replace it, I would probably get the entire unit from Rudy since it looks like the new rudder is now solid, as opposed to foam cored (which I think is what the original is). There are other options out there including the Idasailor. I've heard mostly good things about it but it is a little more expensive. Anyhow, I like buying from Rudy because I know that everything will fit perfectly.
Dave
O'Day 222