I got a chance to take a short paddle in Wenonah's Wilderness Sat.

It takes to leaning OK,,,nice mix of initial and final stability,,,a bit wide paddling for me, but not bad from a kneeling position. I used a straight blade. I'm guessing a bent shaft and sitting with feet on the foot brace it might not track real well and you'd be busy switching sides. Better with a j-stroke and straight blade IMHO.

Would have like to jump into a Merlin II, but a demo wasn't available to compare.

The Prism is a nice boat, but I have only paddled it with a light load.  I agree with the other solo paddlers, frequent trim adjustments based on the wind and yes, tailwinds are much more challenging.
I paddle a Merlin.  For a number of reasons, not choice, I had to remove the seat.  I had a sliding bench seat glassed in.  I love it.  With the footbrace in she generally handles beautifully.  I have often been the only paddler on the water, with glum paddlers campsite bound, staring at the waves. 
So far as paddling a straight line or being able to stay on one side:  I hit and switch, how often depends on which quarter the wind is coming from.  If the wind and trim are right, I can paddle on one side for a very long time.  I'm used to traveling in a sinuous line. 
One of the reasons I like the Merlin is that, unlike it's slightly longer cousin, the Magic, I can lay my packs down flat (unless I seriously over pack).  So far as capacity goes, I'm a big guy (230#) and I have (over)packed it for a 20 day solo and been perfectly happy with the results.
I love a dedicated solo boat.  Someone else mentioned the Wilderness, which I like, too.  If you want something with a little more rocker (cuz, you might need a dedicated river boat, as well as one for the lake country...) check out the Argosy.  Fun boat. 
Nuff said.  Good luck and have fun.

JJS--yeah, I don't think I'd want the Argosy as a lake boat, it doesn't track well enough.  Great for little rivers and creeks, though.  The Rockstar is pretty fun, I've only paddled it briefly, though, so I can't really review it.  My preference for the Merlin is based mainly on the fact that it's what I paddle and I have got to know it's quirks.  I find it has great secondary stability, and pretty good primary with the foot brace.  It's a brave little boat.
Cheers,
gp

Even experienced paddlers need some adjustment time when switching from one boat to another. I go from racing to whitewater solos and can be very comfortable in each. But it always seems to feel funny for awhile, and I've owned these boats of years.

Goldilocks should sit down for a beer and get to know the bears boats.