Over the last month or so I've been thinking about this "start a second manufacturing process" idea, and I'm becoming increasingly less happy with it. Sure it would double my profit and open a second market, but I'm just not sure if I feel like it.
At the same time, it occurred to me that there is a compromise which can be made. I can easily expand my existing process to 5 characters (50 slots) just by increasing the number of blueprints in it. Conveniently, I have enough blueprints in research right now to do this.
The downside is that, since stations only have 50 manufacturing slots, it would be impossible to use 6 characters. However, I have a half-baked plan for using one of my characters to do evil, which would require it to be in a different corp, so that's okay. As for the problem of other people building in
my station, I figure that will resolve itself once I start filling all the manufacturing slots.
As for the current manufacturing process, it's continuing to expand. I recently added a second moros, thanatos, and archon blueprint, which puts the blueprint load at or slightly above what can be manufactured with three characters. Nearly all the duplicate component blueprints it needs are finished researching, too.
A few posts back I wrote about how I was having gaps between runs where component blueprints weren't being used, and how expanding my process to keep three of each ship in production at all times instead of two would solve this. I have arrived at a middle ground here, too, where component blueprints can be kept in production without putting so much more isk into minerals, by keeping two of each ship in production, plus one additional run (4 ships). I started implementing this a few weeks ago, and it seems to be working well.
If I do decide to go with a single 5-character process, it may be necessary to increase the number of ships per run to 5 or 6, just to keep the number of times per month I have to buy minerals down.