I can tell you what I know about GOLD leafing cuz I ve done it much. If u go with gold you have to use the real thing, not imitation gold or you will do it over in 3 days. Its not that expensive but I guess it depends on the size. It would be easier to do without removing the first finish because raw wood releases gasses that can cause bubbles. Most important is that you use the right kind of varnish, which is simply a speed varnish that you buy at the boat store. You put on the varnish first in a small area, then wait till it dries , (30+- min) , till its tacky to the touch but does not catch your finger tip enough to show the finger print. If you can see your print in it, then its too early and you gotta wait a few more mins. DEFINITELY dont put the gold on while the varnish is too wet.
it takes practice , so practice first. Use a soft paint brush to lay in and burnish the gold.
Your big problem is that youre gonna have to seal that GOLD with something when your done, since its a guitar. I dont know what to use to seal it with since Ive never had to do it with sign lettering.
Check around for more info.
Calibration1