If you want it to look like new, don't bother spraying anything on it until you sand off all the old finish.
I have refinished lots in the same condition yours is in, and the old finish can't be blended. Do not be afraid to sand on the glass a little with 150 grit. You won't hurt it unless you go crazy. As you start to sand the finish off the glass, you will feel as well as hear, and smell when you get to the glass.
After the finish is all off I switch to 220 grit and re-sand the entire bow going with the grain.
I use wipe-on poly as my finish. It is very durable, has a nice sheen without being glossy and is very easy to apply. I can recoat 2-3 times a day if I want and it'll fill in the grain nicely.
I've used as few as 5 coats and as many as 20 coats depending if I'm going over new transfers.