I know that feeling, but I say keep 'em going, discerning readers are out there, you just have to find 'em (or they have to find you). It could be something as simple as updating closer to when they're online and they discover the comic.
Making big boom action panels is just as simple, resize panels by highlighting them and dragging them around so they're bigger or smaller. Shrink surrounding panels back, then expand the big boom panel to fill the space.
That's done in Paint.NET but it probably works with anything.[/spoiler]