It's great timing, in a perverse way, but I do have to give myself a reality check on this, too: it's not likely to be too dissimilar from the position that I'm in now. Granted, it probably won't have MySQL and Access behind it, and that'd be great. But the position isn't typography or web/print design work. It certainly isn't publishing. So while it would be moving me away from a position I'm uncomfortable in, it wouldn't be moving me in the direction I actually want to go.
I'm inclined to simply ask for an hourly amount that would give me an equal weekly rate, assuming 30 hours a week instead of 40: do the math, and I'd have to ask for 33% more. If it were 20 hours a week, it'd be just under 69% of my current rate--still handily livable, really. And, of course, if they think that's an outrageous amount, we can just go our separate ways.
The flip side of the argument, of course, is the one I just made--that even though a change to this position might reduce stress, should I be considering a move that isn't explicitly toward what I want rather than simply away from what I don't want?