Welcome friendphil!
Hans (or anyone else) can correct me, but I believe the scale is 24.75"
I assume you have a rosewood bridge with adjustable wheels on either side.
The fact fact that the bridge fell off indicates to me you might not have much experience with archtops w/floating bridges. Intonation takes a little time, but it's worth it when you're done. Assuming the bridge wasn't damaged, I would suggest stringing the outer strings (both Es); roughly tune both to get the tension; see if the bridge height needs to be adjusted - if it does, loosen both strings first,then adjust, then retune. Check intonation at 12th fret for both strings. Loosen and tighten strings as often as necessary to angle the bridge such that both are intoned.
Then string the rest and they should fall into place. Depending on your playing style, you might want to use finish-safe carpet tape or other adhesive so the bridge doesn't move when you play. I personally don't, but others here on LTG do and can give you their opinions if you need to do that.
What kind of strings are you using? Assuming you have compensated saddles, remember your string set must have a wound G.