Have you changed the stats for the Great machine weapons platform? Because if you haven't, trying to deploy the GM will be kinda hard...
It is 20,600 kt
A huge planet (with homeword atmosphere) has 16,000 kt of cargo space. Adding in a HH and depot gives a total of 26,000 kt, leaving little room for anything else. Colony Hub plus Manufacturing colonies plus depot does the same. Frankly, I only ever built one, just to see it in action, and it crippled that planet for use as a staging area. I suppose you could just build several depots to allow it to be housed (or get a bit more slack if you have AST), but ...