I don't know what it takes to get an account on the wiki, but I found an error...
You can fit a Laser Cannon Mk. III module in a Small slot on a Spire Cruiser.
Edit: On further investigation, it turns out that there are four slots that can take a Laser II or a Rail I, but only two of them can fit a HBC I whereas the other two can take a Laser III.
If I had a good suggestion for a better naming scheme, I'd propose it. So far, I'm only coming up with "Beam" and "Turret", but they're all turrets. Maybe Small, Medium, Beam, Large, and XL(FF)?