Well, I deal in American vintage horns, so here is my input.

Conn rolled tone holes work wonderfully with Conn Resonator pads. If set up correctly, the right pad sizes fits  snuggly, no glue is needed. But if other pads are used, they are glued in. Small adjustments can be made to remove minor leaks, heat gun. Raising the pad slightly using a large needle, like a baritone sax needle spring. Bending keys to close a leak is not something I would do. The Bell keys are on the left side of the bell, sort of old school. The keywork is somewhat primitive, considering new horns have the most up to date Selmer type keywork. Conn keywork will also bend easier than keywork that is "hard stamped" out. But, nothing beats the old Conn 10M sound if that is the sound you are looking for. The vintage 40s to 60s sound.

The other two models are newer horns. Truly the decision is up to you. Value wise, Id prefer the Conn if it was cosmetically original. It will hold a good value depending on what you pay for it.

Id stick closer to 2600 or less on that particular horn. Look around at what is being charges for a 10M from the sax sites. Saxquest, Junkdude, PM winds, Tenor Madness, if you can deal with their new quirky web site.

There is too much input from one stranger.

Buy what you like. Thats the true advice here.

Good Luck