Standardisation would seem to be the no-brainer to me too. Standard sizes of cargo bay hatches, that can mate with a same sized one for a convenient cargo transfer. At the very least, ships built on the same standard hull should be able to manage it between them, unless the hatch is really poorly placed. That is, a Type A1 or Type A2, or many refits of that same venerable hull design could all line up their identical cargo bay hatches and lock them in place. The ships might be upside down in respect to each other, but g-plates... and Space.