Stumbling around dusty parts of the blogosphere this evening, I happened upon two posts that I am fairly certain I read once upon a distant year.
The first and more important, I think, is Ars Ludi's plot grid, whereby a game with an irregular player base might have a plot rather than going full-episodic. Also comes with the neat feature that less-frequent players are more likely to have the sessions that they attend center on their subplots. This is a thing I would have been well-served by in either of both ACKS games, and in retrospect bears a lot of similarity to how I managed my notes for Traveller back when. Also interesting that even with a player pool of 30, he was pulling 3.4 players per session on average.
The second is Justin Alexander's post on the open game table, which I realize now was almost certainly an influence on my gaming development over the last few years. The pair of interesting take-away points from this most recent reading, however, were that the pick-up style is not the end-all-be-all of the RPG form, and that when he does scheduling, it's in one-month chunks, as opposed to the one-week chunks we were using for ACKS. I think that's an important administrative insight, as one of the things which was tricky with Scaled Continent was planning for a particular group mix with just a few days of lead-time. There was no way I was going to be able to tailor anything to anybody due to lack of data on my part plus short timescales.
With per-player plotting and month-lead scheduling in mind, my willingness to run a campaign for irregulars over the 'net is somewhat increased again. Still need to fix technical issues with voice/vid for it to be really workable, though. Somewhat concerned that I may have blown my credibility in that arena, but hey, the first couple runs of any new setup rarely go smoothly.