I know a man from Soileau that couldn't put it down. I also know it survived some pre-mardi gras drunken hooliganism in L'anse Prien Noire, so I'd say she's ready to pull the stops up and get down!
Being a softer wood, the spruce will ding easier than a harder one, say like maple, as will some made out of pine or cypress. Unless you plan on dancing on one, the strength of any accordion has more to do with the construction than the wood as it relates to regular use. The strength in the corners has little or nothing to do with the metal corners, there are wooden corners on the inside, and that is the true strength in an accordion frame.
Those metal corners are mostly decorative, and to keep the corners from getting dinged. I'd say most accordions made in Europe do not have metal corners, and a lot that do have them probably do because they are making them to look like Cajun accordions to appeal to that market. I don't use the conventional ones because everyone else does(tradition), and I don't really like them (not knocking em), and I just wanted to be different.
The big worry with my lightweight baby, is if someone goes to work on the reeds not knowing what the blocks are made of, can tear the block up taking a reed off if not careful. Other than that, there is no stress on the reed blocks, so really shouldn't wear out.
The slides are conventional aircraft plywood, and I reenforced screw holes with hardwood dowels.
For slides, everyone I know uses the same type plywood I do. The dowel thing is actually an old woodworker thing, often using a metal threaded insert. I've used both in furniture but was timid about doing it with accordions because I was worried about not having enough room in the routed profiles of the frames. I didn't do it on my first one, which is made out of almost rotten cypresss, and had a lot of problems with screws stripping. After talking with Rusty Sanner, I tried it on the redwood one I made for Chuck with no problems, but went through on this little black one. It's a lot easier just to use a hardwood to begin with.