You'll have to remind me, just how tall and heavy is your stoker? I'm not being a smart-ass and I'm not trying to offer any definitive advise on tandem geometry because you can play what if games all day. But, after 11 years, 40 tandem rallies, and riding with thousands of other tandem teams you do pick up on certain things along the way. This thread like all threads about steering geometry will always have highly subjective overtones because bike handling is highly subjective.

That said, the reason I introduce stoker size is that the stoker's height, weight and riding style will usually do more to alter how a tandem handles and feels moreso than anything you can do by changing a fork. Small kids can do handstands on the back of a tandem and still not create as much 'work' for the captain with regard to keeping the bike going in a straight line than a 6' stoker who likes to peek around the captain's head. The more trail you add to that scenario the more dramatic the effect and the more 'work' the captain must do to keep the thing going in a straight line.

Also, getting back to the OPs conundrum, you can also screw up the handling of a tandem by selecting a fork that's just not stiff enough for your preferences. Alpha Q forks, for example, have a noticeable amount of deflection... far more than any of the other tandem-rated carbon forks. That additional deflection makes our tandems handle differently than they would with a stiffer fork with same or different rake. It was somewhat unsettling at first back '02 when we made the change from our lightweight (850g) custom steel fork to the 500g Alpha Q, but since we're a lightweight team and I float around in the 160-170lb range over the course of a year, the deflection is acceptable. Again, nothing's simple and you can add all kinds of things into the equation to make it even more complex.

You'll have to re-phrase the question as I'm not clear on what you're asking. If the question is, does the average consumer even consider geometry when they're shopping for their first tandem? If so, then the answer is no, and that's probably a good thing. Geometry shouldn't become an issue until you find that it is an issue, real or imagined. If you're talking about a Cat 2 out shopping for a racing tandem to use at the Co-Motion classic, they might opt for a 'racing tandem' based on reputation and component choices but, then again, they might just find what ever tandem they can get their hands on that fits and simply ride the snot out of it. Neither of those probably answer your question...

Nothing wrong with that and all I'm sharing are my observations and opinions and purposely try to keep it simple. Again, the best way to figure out if any of this matters is to ride different tandems back to back under similar circumstances that mean something to you. If you'll never have a 200 lb stoker on the back of a tandem, then you'll never need to worry about how much more or less suitable a Co-Motion or a Santana might be, in much the same way that the strength and durability of a rear wheel may ever become an issue.