Apologies, this is a bit of a wall of text, but I swear there's a point to it. The model is described by them as:
JA Bell: 8.5-inch, two-piece, hand-hammered “TI” taper in lightweight yellow brass with traditionally brazed seams, unsoldered bead, and special annealing treatment
I would suspect that the closest nomenclature would therefore be a 2YLWA
n where N would be the annealing number. In the Shires Q&A thread from the old TBC, Ben (from Shires, at the time) mentioned:
4.) You will forgive me if I do not reveal completely everything about annealing treatments. In general, annealing will provide a slightly warmer sound and more timbral flexibility of lower overtones, sometimes at the expense of clarity/brilliance. In general, I recommend these only to specific players. A4 for tenor, A5 for bass, and only on particular models.
So, it's probably something really similar to a 2YLWA4. That said, what slide do you have? What leadpipe do you have in it? The "Q" slide is probably the equivalent of a TW47 and probably had a "2" taper leadpipe. If you have a TB47, T47, etc., and a "1" or "3" pipe (or it was a different pipe), everything you've said makes total sense. The slide, especially the lead pipe, makes an enormous difference in how something responds.
Something I will caution you on is this statement:
I wasn't a fan of the valve thought, I think I'm just more of an axial guy.
Given your description, it kind of sounds like you were a fan. In my opinion, it's not uncommon for people to over-index the importance of the valve for the whole setup. For Example, say, "I want a trombone that works well with a Thayer valve," rather than, "I have a set of components, and I want to find an appropriate valve that works with this setup." There are very valid historical reasons for this; for example, Bach 42 was really popular (and still is), and when the Thayer valve was released, it was common for people to replace Bach valves with aftermarket Thayer valves. This setup worked well because Thayer valves tend to work well with a Bach 42-style setup (Bass crook, compact leadpipe, one-piece soldered bell).
The one combination it does not sound like you tried was the Alessi bell on your Thayer valve and slide, yet that is what you want to purchase; do I understand this scenario right? Is it feasible for you to try it first with that combination?
My experience is, and you should take this with a massive grain of salt, that type 2 bells do not work very well with Thayer valves. Likewise, I typically don't like type 5 bells with rotors. I've played exceptions to this, but I wouldn't buy one of these combinations blind, personally.
Type 2 bells have an unsoldered bell bead (as do type 8 bells), which generally favors a broad/wider sound. Thayers also tend to contribute to this sensation, so the combination of these together (especially with an 'open' pipe like a "3") will make ahorn feel really unfocused to me. On the flip side, Type 1,5,7 bells have a soldered bell bead and are typically more "focused". Type 1 is a traditional two-piece construction, Type 5 are one-piece (like Bach bells), and Type 7 is a method of making a Type 1 with weight distribution that has some of the positive characteristics of a one-piece bell.
Given your bio, you either put your Bach 42 slide on it or your Q30GA slide on it. I'm guessing it was your Q30 slide, which should be pretty much identical to the QAlessi slide. As such, I'm guessing a few things:
1. The leadpipe in your slide worked better than whatever leadpipe was in the demo.
2. Depending on how you tried these bells out, something was off about the slide you were playing on (not rare at all, especially at a show/convention or demo instruments)
3. Part of what you liked about the setup were the compactness that the rotor gave you.
Each of the valve sections has pros and cons, as do every other component. Something else you'll hear people say is they like "positive attribute a" from something (like a mouthpiece), and they want that but "positive attribute b" a different component. As an extreme example: "I want a mouthpiece that feels as open as the 4G I played, but with the high range and clarity of the 12C". Well, those attributes might be mutually exclusive, often times the equipment we choose has a tradeoff. A rotor on a type 2 bell is a popular combination, among them, the focus you get!
Now, I am the king gearhead. I like trying components. I've bought things that I suspected would be total flops. I was right most of the time. Sometimes I've been surprised! I think it's fun to have a variety of combinations. That said, I think your approach to try to part out piecemeal might not be the best use of your resources. I would recommend going in with an end-state in mind. So if you've already tried a Thayer with the Alessi and a gold brass slide, by all means, disregard this.
On the other hand, if you want to have a set of components that works well together, I'd try to find someway to try out all of those combinations and do something such as 1) order a bell and tuning slide that works with the Q30 slide and Thayer valve you have or 2) replace the whole bell section with a bell section where you've tried each component in unison or 3) something else you haven't considered.
It sounds like you liked the focus you got with the Alessi bell section on your Q30 slide. If focus is something you think you lack (especially given that you already have a Type 1 bell which traditionally is more focused than Type 2), you might want to consider a few things:
1. Have a good tech make sure your bell section is built without stress. Ensure that your thayer valve isn't leaky and is properly oiled. Ensure your slides (tuning and hand) don't have any leaks, are properly aligned, etc.
2. Something that is less "open" than the leadpipe you have now. (If you're on a 2, a 1.5 or some of the Bach 42 replca pipes that are in vogue now might be a good, much less expensive than a bell).
3. A valve that is less "open" than the Thayer you have. Shires has like 8 million valve options.
Or, in short, it seems your priority here is to have more focus, and you are proposing three components that I would typically associate with a broader (at the expense of focused) sound. It might work out, but if I were betting on it, I wouldn't necessarily take those odds.