Those look cool. I feel like I'd need to see a 3d view around them (or a video) to fulliy understand their geometry. Haven't tried searching Youtube yet.
In any case, I decided to dive in and see how much I could do with just plain old sandpaper. I will work as slowly and carefully as my patience will allow (I'm allocating weeks for this job, doing just a little bit each session). My first run has been pretty good; there are a few crevices I didn't cover well but they are probably OK. Also, despite my attempted gentleness, I did sand through to the wood in one or two spot on fin edges. I think when I'm done I'm going to do a targeted coat (just the areas I want) of primer, just to cover up the few small spots of bare wood. Long way to go before I get there though.
For the nooks and crannies I use the Lee Valley sanding grips. They are precise for fillets and they help with fatigue for those long sanding sessions we all love.
https://www.leevalley.com/us/wood/page.aspx?p=20183