I've been trying to clear out product, with a fair degree of success. This has left me with quite a lot of liquid isk, so I decided to buy the remaining component blueprints for my second capital manufacturing process. There were seven of these.
Turns out, though, that between all my characters I only had 6 research slots open. I haven't really thought about that as a limiting factor until now, and I still have 7 ship blueprints to buy.
Nbd though. In this job I'm used to waiting.
The answer is "51", in case you're wondering.