Finally finished the conversion earlier today. I'm happy to say it's a success.
I had to do a little more work than I thought, but it was worth it.
For some reason, the bridges on the DC3's were drilled slightly different than the 59's and 56's. I couldn't simply drop in the sitar bridge. As a result, I had to drill two more holes for it to fit.
Also, I had to cut off a little bit of the bottom end of the pickguard to leave space for the trapeze tailpiece. I sanded it off to give it some curve.
Still need to tweak the sitar bridge though (that's gonna be a whole nother struggle).
I couldn't attach the picture, so here's a link:
Edit: Finally finished setting up the bridge. Olddawg, you weren't lying when you said these things were tempermental. Getting the strings to buzz was one thing, but getting them to intonate was another. Getting it to do both was almost the equivalent of Frodo getting the ring to Mount Doom. I've got a nice buzz going on and the strings surprisingly intonate very well up and down the neck. The tailpiece has been sturdy as a rock too.