That's a great site! I love the Schilke Loyalist site!
It doesn't seem to me that there is really a rhyme or reason for the numbering system. I've just learned this or that about them, mainly from the Schilke Loyalist site, but also from the Schilke Musical Products site, from reading about the various models. I think that Renold originally started with his favorite, the B1 (B stands for 'Bb'?) and then came up with other models and designs to fit various purposes and "needs". He was a smart guy and I think that he realized that different players were going to want different things, hence the prototyping and designing of the various horns.
I was going to suggest that the numbering was the order in which they were prototyped and released, and that sort of works except for the B4, which was released after the B1, B2, B5, B6 and B7.
At this point, I own a B6 - if I ever become richer than Midas, I'll own one of each of the B models! (Of course, these will be hung in my display room/studio on the wall adjacent to my Monettes.
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