Honestly, since starting this thread, I've only sold a couple handfuls. The first issue sold relatively well at the convention I tabled at, but sadly no returning buyers for future issues.
I think the best thing to do is make sure the demand is there for it. Gauge interest from your readers, maybe put it up as a pre-order book so you've got some definite figures ahead of time, and maybe do a small print run, see how it goes. Best of luck.