Whenever I start a thread with a question, I like to follow up with whatever line of advice I followed and how it's working out. As I mentioned I'm building a new Skyray disguised as a Streak and was asking about finishing part of it with a natural wood finish. Not a showpiece, just a decent looking utility plane. Paul Wood and Ray Copeland both said a couple of coats of Minwax Polyurethane would do the job.
So it's coming along nicely and I've started coating some of the parts. I lightly foam brushed the parts of the elevator and stab to prevent warping while waiting to be hinged. I sanded it thin and smooth and while gluing the hinges in I had to wipe some epoxy off of the wood with acetone. It didn't faze the urethane. I also tried alcohol and it was equally impervious to that. Very encouraging. Boy, a tiny bit gives great coverage too, I really like it. Here's what they look like after the first coat before sanding, which made them look even better.

It's all hinged up with the second coat drying now. The fuse behind the doublers will also get the bare look.
Here's the rudder, still needs some shaping to get some fat out and the proper Streak curves.

I'll pick a color for it after I paint the front end. Since I'm using aluminum Monokote flames on the front of the wing with Sky blue behind it I'm hoping to paint the nose and doublers Krylon aluminum. I have a test board drying to see if that paint can withstand Lustrekote or Minwax. If not, I'll go yellow on the front, and then decide on a color for the rudder. Maybe yellow, maybe silver. I'll cut the Streak shaped wingtips after mounting the wing and adding the flaps.
Anyway, that's what I came up with after starting this thread. Thanks for the answers.
Rusty