Well, after two days of test runs, I think I've figured out what went wrong with my CO2 regulator and I think I've fixed it. I'm planning on running it through the weekend to make sure it's reliable before I put any fish in the tank.
Speaking of which, cycle-wise -- given that it's a decently-heavily planted tank, that I'm pretty sure I have a virtual army of MTS patrolling my substrate, that I haven't yet changed my top filter pad (even though I need to), and that the tank was cycled before the disaster -- so long as I add new fish slowly and keep an eye on my parameters, I shouldn't need to run out and buy a new batch of bio-spira (or otherwise re-cycle the tank), right?
I'm not 100% sure what I'm going to put in it, but I think it's going to be fairly similar to my old tank. The core idea is:
8-10 Pencilfish
7 Zebra Loaches
2 Siamese Algae Eaters
And then I'm not sure about feature fish and plecos. For the plecos, my initial instinct is: 2 L-134 Leopard Frog Plecos and 2 LDA-08 Gold Marble Bristlenose Plecos, just because I've kept both and enjoyed it thoroughly. But I could also see going the Hypancistrus route, or getting one L-134 and one L-204 (although that might mean adding more driftwood later on). I'm not sure.
For feature fish, I'm even less sure. I could very well go back to a trio of Rainbows, and I'm definitely going to have some kind of cichlid as the centerpiece, but I don't know what I want to do. I'm considering a pair of Rainbow Cichlids, but also considering a few pairs of apistos instead. And then again, Pure has
offered me some angels. So, I really don't know yet - but I'd be thrilled to get others' input...