Well, we may have a winner here:
This solid tube model
finally came in, and I have to say that this is one of the most comfortable units I've tried.
I had ordered a spare ring to experiment with, and ended up removing the integrated lock section to wear as a full-time cock ring, and I'd been very happy with that, so I ordered an entire cage for less than $20.
I had some concerns in ordering the 45mm cuff ring because it's only a hair over 1-3/4", and I prefer the 1-7/8" solid rings), but the ergonomic shape (it's a cast ring) is surprisingly comfortable to wear. I was concerned that adding a cage and 4am erections would be painful, but it turned out to be barely noticeable.
The width makes it less likely to move around or slip, and the cage itself is surprisingly light weight (the unit came in just under 6 oz), making daily wear much less of a problem than my 12 oz Fort.
While I do prefer the shape of the Fort/CB3000, this has an open-end cage that makes it easy to use at the urinals, and easy to keep clean. Size-wise, it's just a bit smaller than the Fort/CB3000: 33mm (1-5/16 inside) vs 35mm (1-3/8) and 60 mm long (2-3/8) vs 70mm (2-3/4) - but measuring the length of these things are tricky. The inside diameter is just small enough to keep me from slipping out, even in the shower, while the Fort needs one of those KSD inserts to keep things in place - although that's partly due to the weight. Also, the size and shape of the cuff ring make pulling out (for me) more difficult. Of course, this is in a shower in the New England winter; it's possible that a shower after a hot summer day when everything is loosened up may be different.
It came with a ring with 3 pointy teeth on it to fit across the guide pins (the teeth are underneath), but they were too painful to even put on. I had a chance to grind them back to something more reasonable, but not sure when I'll get a chance to try them.