I haven't posted in here for a while, but the fiancee and I just got some new toys, so I have to show off!
I ended up going with the Altamira I mentioned when I first joined the thread. Unfortunately, the bike ended up being quite a bit too long for me, to the point where it started causing me back pain after about 28 miles. Looking at standover height was the extent of the "fitting" performed by the shop where I got the bike; I know better now. After talking to a fitter at another shop and trying some fixes on the Altamira, I ended up with a Trek Emonda SL 6!
It's a lot more bike than I need for sure, but I got a really good deal on a 2016 model and it has completely solved all my back problems. I have to say it's pretty attractive in all its murdered-out glory. It's maybe a bit more relaxed in character than the Altamira, but it is supremely comfortable. We did the ride that always gave me problems before on Monday and I ended up riding a few extra miles just because I could do so without any pain. It's maybe a bit slower than the Altamira due to its compact crankset, but I hit 39.6 mph on the biggest downhill according to Strava, which is pretty fast for me, and I was still pedaling.
As for the fiancee, she got a Diamondback Airen Sport as a Christmas present from my parents last year which, and even after upgrading to a full Tiagra groupset from the mix of Claris, Sora, FSA and Tekro parts that was on it, she wasn't really happy with it while trying to keep up with everyone else on the rides. The DB was pretty heavy even for an aluminum bike and I think the last straw was seeing my mom, who has typically been pretty slow on the rides, improve greatly by moving to a racy carbon bike (a Giant TCR Advanced Pro Team; also an amazing bike.) Luckily, the shop we bought the Altamira and her Airen from offers a 100% trade-in within one year of purchase, so we were able to trade in both of those bikes on a Fuji Supreme 2.0 and basically break even.
(Don't pay any attention to the seat height; we hadn't set it for her yet.)
It's a really nice bike from what I could tell pedaling it up and down the street this afternoon. Supposedly it's basically an Altamira with a cut down head tube, which sounds great to me. She hates the way-too-squishy seat, but we're going to be heading out to the
Silver Comet Trail this weekend to attempt a 67 mile jaunt, so we'll see how everything goes!