True friendship is letting a small havenworlder ride around in a pouch that you're wearing so they feel secure surrounded by the other deathworlders that they wanted to do business with in the first place. Seriously. Why do you do this to me? -- Escla
Size is something interesting within the boundaries of Galactic Alliance space. Intelligent life can take very many forms, depending on the gravity they evolved in. There are some, like the Xyrak'l, that have shown signs of intelligent behaviour, yet exist in a gigantic grey zone to everyone attempting communication with them.
Most life exists in and around one Standard Gravity. In that, there are certain forms that occur for cogniscent lifeforms. The anthropoid form tends to predominate with some... peculiar modifications on the central model. Evolution only has so much to work with. You can find cogniscents in the one-gravity realm in sizes between that of a terrier, and that of a bear. Which lead to some... interesting solutions for communication and social mingling.
Consider... the Buddy Livesuit. A larger cogniscent carrying -on their chest or over their back- a smaller one in a reinforced pod or bubble. A larger cogniscent - usually a friendly Deathworlder - carrying their smaller Havenworlder friend around for trade negotiations and sometimes simple transport. Human Engineering, so you know it's tough.