Firstly, welcome. These are truly a fantastic set of speakers when back up to specs. I too am in the camp of hating Oak cabs, but I am a woodworker and Oak sucks to work with, and frankly is boring.
Coming in a bit late perhaps, but on the topic of refinishing them: First, pull everything out of them (if your skill level permits, if not, cover the hell out of everything with plastic and painters tape). You are going to makes some dust and you do not want that in them. Second, you may want to do a light stripper on them. It's been a while since I have had my hands on mine, so suspect there is a very light poly coating on them. It wont hurt anything if there is not. Next, sand with a palm or random orbital sander (this is where having all the drivers and crossovers, etc. OUT of the cabinet, would help) Oak is a very heavy grain, impossible to get baby butt smooth. Start with a 120 grit and following all grits not skipping each one. I always over sand. I typically go to a 400 grit, but 320 would do fine. Call it my wood OCD sydrome. Following that, stain to your liking only after you have run tack clothes across it several times. Get rid of all the fine dust. After the first coat of stain, you will notice the grain will become more proud. Your choice here. You may want to lightly sand again to knock it down, but be prepared to stain again potentially. As this is not fresh wood, I probably would not use a stain conditioner. However, if you do not have a bunch of experience, it would not be a bad thing. Stain conditioner forces the wood to take stain at the same rate, which will eliminate "hot" spots (blotchy spots). The clear coat selection is where things can go astray. Tack clothe again and between each and every coating. Dont skimp on this point. I would recommend thinning Polyurethane and ragging it on in extremly thin coats followed by extremely light sanding. Why you ask? Because if you are not spraying it in a professional set up, chances are slim to nill it will come out right. By slowly adding coats, you minimize the chances of orange peal and brush strokes. Light sanding between coats ensures you get it right. It will take about 4 coats minimum via thinning, but you can get a pretty damn smooth coating once it is all said and done. Alternately, you can use oils rubbed on. Linseed is affordable and results are dependable. If you go the oil route, you will need to re-oil again at some point. Not sure of when as that will depend upon your climate and UV exposure. Oil is a safer route than the polyurethane. It is more likely to preduce a smoother finish.
I too bought a set with broken grill wood. Use the old ones as templates and find a band saw to cut them perfectly. Cover with new clothe.
Check your caps for leakage!
Check your emits and emims. These can be repaired provided the membrane is not torn. Instructions on repairing these is well documented here as well.
Check your woofers for brittle foam Are they paper or the gray poly? It makes a diferrence. Refoam them as they are due.
When you go to rewire them, make sure you get it right. Plenty of information here on these great speakers. If in doubt, reach out and someone will help you get it sorted out.
Enjoy and have fun with it. It is a wonderful feeling to put right some of these old classics like these! Your ears will thank you!
Cheers
