Hi Bob,
The L&R Bailes locks are perfectly suitable for a double gun and if you look at doubles by Nock, Egg, and others from the late 18th century before inset or stepped breeches, they look OK. My complaint is simply that they are almost the only game in town and really limit what you can do. The Durs Egg lock is bigger and in my opinion, the Bailes is already big for a double. Double locks were typically 4 1/2"- 4 5/8" long. The bigger the lock, the harder it is to keep the stock slim at the wrist but not too wide in front of the locks. This is particularly true because none of our modern locks will work with inset breeches.
dave