I pulled a sample and it's at ~1.020, down from 1.046, after ~54 hours so it's definitely been working. Considering I didn't see anything for activity in my blowoff tube arrangement (in first use on this batch) I pulled the fermenter cover and replaced it with the original that takes standard three-piece airlock.
There was definitely some high krausen in there at one time and still was a pretty good head of foam although it appears to have receeded from the highest level (which touched the inside top of the lid with a bit over 5gal wort in 6.5gal bucket).
Either it erupted in activity which I completely missed (hard for me to believe since I checked pretty often), or I have considerable air leaks in my supposedly sealed system (lid with o-ring). Thinking the latter.
Now my worry is that it doesn't hang at the dreaded 1.020 blues.