Hi
You say “They situationally outperform the regular cargo bay without replacing or invalidating it”, but in fact, as soon as you have two bays, they outperform a standard bay and you no longer have any reason to use them.
Two regular ones have : 2 pod hatch and 40 slots
Two of the custom ones (1 of each) have : 2 pod hatch and 55 slots
This means that your bays have the equivalent of 7.5 extra slots compared to the vanilla ones. For a ship with 10 bays its 75 bonus inventory slots !
With legendary ones, this is 18.75 extra slots per bays, so 187,5 for a ship with 10 bays.
I find the concept behind the mod interesting, and I think it would really make sense if the balancing were done in such a way that one of each corresponded to two standard ones. In my view, these specific features are enough to make them useful, without them being any better than the standard version.
This would provide options for rapid unloading or large-capacity storage for specialised ships, whilst retaining the usefulness of standard bays for large, multi-purpose vessels.
So, that was my thoughts on the subject; what do you think?
Have a nice day :)