Hey @fleetinginfinity! I'm currently working on a long form comic (just over half of the first chapter has been posted). I will say that I think it's harder to keep an audience with long form, especially if you're only posting once a week like I am. It makes it difficult to build an audience because you have to hope that people see it that one day of the week it's up, and then you also have to hope they'll take the time to catch up on the story.
I made my first chapter into an action scene in hopes of building an audience before it becomes very much a story driven comic in chapter 2. The only downside to that though is I can't really promote it for the comic it'll be starting in chapter 2, I can't talk about any of the story elements, or the main characters, because they're not in chapter 1. Makes marketing it a little difficult.
You and I also have an extra hurdle in that our comics are black and white. I've gotten numerous comments saying "I'm not usually into black and white comics but I like what you're doing" - which means probably a lot of people won't even give it a chance without color.
Honestly the best thing you can do is post on the forums, follow other comics, comment on other comics, those I've found is the best way to gain subscribers (and I've only recently reached 30 :P) So your number of followers after only a month is a good start!
Good luck! And I'd love if you'd check out my comic when you have some time!