Or in my case, when trying to figure out what to buy. Referring back to my first post on this forum:
http://www.bikeforums.net/showthread.php?t=294295

I guess I never said how all that worked out. Our first two tandem tests were on borrowed C'dale and Davidson. We rode each several times, probably a total of 100 miles each. No problems, but we didn't feel like we could make either bike really "go." Then we had a disastrous test ride on a Co-Mo Primera, described in somewhat mellow terms in the post referenced above. Much mellower terms than what we really felt during the test, not wanting to rank too much on someone's pet bike, but we barely got out of the parking lot without crashing into someone or something. We had trouble staying in a 3' imaginary bike lane on the climbs.

We did not go back for a second test. Our ride had been a good 15 miles over varied terrain, and we felt we had a good feel for the bike. Instead, we had faith and bought our used Speedster with Wound-up fork, sight unseen. We rode this bike perfectly from the first pedal stroke. No instability, no stoker steer, no feeling of frame flex, etc. Not a subtle difference. From what TG says in these two threads, the Wound-up with its slightly greater trail should have disposed the bike to increased stoker steer, low speed handling issues, etc. But it was the opposite. Something about the Primera's handling was stimulating my stoker to try to compensate. Whatever that was, it does not exist on our Speedster.

The only thing I can think of is that the Primera's steer tube was not cut down to no spacers on the headset, like our Speedster. Rather, about 3" of spacers were under the stem and maybe the steer tube was flexing like crazy. The dealer said they always left them like that until sold, to accomodate buyer preferences. Or maybe the stock fork is not nearly as stiff as the Wound-up, which gets back to the OP's question. Though TG seems to be saying the opposite. And kudos to TG for presenting a consistent story through all these threads.