I'm interested in knowing how the process goes on. Just out of curiosity, have you got pics of the body before the Tung oil, and one with the Tung oil without the varnish? Is applying the Tung oil like sort of painting it some other colour?
I understand that this is a new body, isn't it? It's not that you've put some kind of varnish on the transparent plastic -or whatever it was- to make it look like wood, is it? Because you said you intended to change the body to a lighter alder one, and that the neck would go, too... But then, are you transforming a guitar, or making a new one? Maybe it's a stupid question, but I've often read about people who buy a guitar and immediately change the neck, the pickups, the electric circuit, the tuners and the knobs, and I wonder why they bought a guitar so to their disliking in the first place. It's different in your case, when you've had the guitar for a long time and then see its disadvantages and what you don't like about it, and then use parts of it to make another guitar. But I know people who go out of the shop already knowing the changes they will do to the guitar. Perhaps it's that I don't know enough about guitars, but I think that if I sat at a shop trying a guitar out and I didn't like it, I'd look for another one, instead of buying it and modifying it the next day.
One of my guitars also underwent home-made cosmetic surgery
. It was the last time I stopped trying to learn to play it. It was a cheap one, so I thought I wouldn't lose too much if it turned out a disaster, it not being too good and I not being able to play it. After much thought, I didn't even remove the varnish and original paint. I just sanded it very slightly and painted directly on the remaining varnish, and on the pickguard. I cannot believe it, but the paint is still there after four years. The result was good enough for me to take it to a luthier and ask him whether something could be done to prevent it from peeling off some day, but it would have been much more expensive than the guitar itself, so I did nothing.