If the wood is wicking water
and wet internally you probably need to replace a little more than what you're seeing as rotten. If it's still pretty solid you might save it with CPES. The PO of my boat replaced a lot of the deck
, but only the soft areas. Now, after six years, the rot has progressed in the places that weren't replaced. It's been explained to me that it's a kind of life form and you need to be pretty aggressive in killing it. I hate the comparison, but it's sort of like cancer in humans. I prefer to think of it as more like rust in metal. I'm sure you know what type of wood to use for your repairs
and have a source. Also to eliiminate the source of water gettting to the wood. I'm doubtful of the accuracy of your diagnosis of, "dry rot".
Anyhow, I'm fighting the same battle and having to deconstruct a lot more than I'd like.
Living the dream.