Nice comparison Trent. My experience with the tuning bell Schilkes is fine up to mezzoforte after which the transition to loud is much less controllable than bells with braces. The brilliance just takes off - which is fine for big band jazz or combo work, but in a classical setting becomes a liability. Countless tests with sound posts did not solve my problem.
I liked the original B1 bell and the Kanstul Benge copy best. It had the right combination of core and halo for my ears. The other three were very good but not as balanced in tone/core. I have a student with a tuning bell Schilke B1, B6 and a modified C. The B1 and C trumpets have the best balance and playing duets has sum and difference tones bouncing all over the practice room.
For my tuning Bell Bach 229H, I developed a brace for tuning slide bells. That gave me the response advantage of a brace and the intonation advantage of the tuning bell.
If I owned that horn, it would also be a keeper. It is so much different than everything else and thus broadens the palette of colors that I could offer.