Nick, I'm surprised to see so much flame "fade" in the 20's F.
Eric, You were running in a little colder temps, so flame fade makes a little more sense, but I'm surprised you had to adjust the knob so much.
Putting the canister in liquid water will moderate canister temperature changes and should give you a more consistent flame. You can use a little butter/margarine tub (very light) with a CCF cozy around it for the water. If that's too much fiddle factor, then the Whisperlite may very well be a better choice. Your fuel consumption will probably be higher with a Whisperlite, maybe 75g/day for solo use because of priming. I've got some tips for how to get the most out of white gasoline stoves if you are interested.
For solo snow melting, I usually take a plain 1000ml Snow Peak Ti pot. It's not the most efficient. My Jetboil 1500ml (I think it's 1500ml) GCS pot is more efficient, but in calculations published by Tony B (a BPL member), he found that the weight of the heat exchanger was greater than the weight of the fuel savings.
Nick, I too have used a Dragonfly for snow melting. It's heavy, but it CRANKS out the heat. It's also very stable with a big pot. It is freakin' loud though. You can get after market "silent" caps, but they're very expensive. I know a guy who is DIY'ing some new models of after market silent caps. I'll post on BPL what his prices will be like if and when he makes them publicly available.
Adventures in Stoving