I've found that Manufactoring hubs and Colony/homeworld hubs are the worse thing you could put on a planet with lots of slots as you can only have 1 space yard on a planet and the above count as one so no Colony hub and a space yard on the same planet
. This gets even more anoying whn trying to build other stuff afterwards as. eg. a colony hub can produce with 300 minerals a turn. However it will lower the minerals/turn on a planet even if with out one the population creates stuff using more minerals per turn.
eg. the population of 4000mil on a planet builds at 1600minerals/turn. I'f u stick a colony hub on it reduces it to 300min/turn and just adds on a production bonus for population size !!!!!!!!
This is why i allways build a space yard on all my planets first even if it takes about 2yrs to do it as after that building are produced much quicker!