Mike, thanks for your thoughts.
I don't think Tormek has really addressed this issue. That may be because the interchangeable wheels are a fairly new addition to the system. And/or because many of the specialized wheel users may not change wheels very often. For example, a turner using high speed steel tools might just leave the SB wheel on the machine. A carver might just leave the SJ wheel in place and "refresh" sharpen often.
Like you, I am leaning toward vertical storage. I know it's overkill, however, I happen to have the older Tormek water trough and stainless steel shaft in my Tormek accessories/spare parts box. I don't remember if the EZYlock shaft replacement kit included a new washer or not. The stainless nut would certainly work with a hardware store stainless metric bolt. (I'm not losing my memory; my Tormek is 150 miles away from my computer. I'm in the process of moving.) A half inch bolt would work fine, too. The water trough is perfectly sized, although part of a quart plastic bottle or something similar recycled from the kitchen would work just as well. Changing wheels would mean changing the water in the trough. A very short "spin cycle" without water should mostly dry out the wheel.
I don't think I would be doing much "on the fly" changing between the standard wheel and the SB. Sharpening my jointer or Lion trimmer blades is more of a separate activity. Likewise with sharpening a dozen drill bits. If I needed to touch up one drill bit mid project, I don't think I would bother changing the wheel.
The SJ wheel was a very recent purchase at a rare bargain price. Time will tell if it replaces my old fine grit water stones. I don't think I would change wheels mid project to resharpen a single chisel. The leather honing wheel seems more efficient for that. I would be more apt to change to the SJ wheel after sharpening several chisels and perhaps a couple plane blades. This would be an end of the day or end of the project chore. I set the wheel distance and vary the blade projection to change bevel angles. I would sharpen all the blades with the regular wheel before switching wheels for honing.
Ken