[Arralen]

Ok, here's my suggestion for tweaking the size of domed planets:

Make them size 2/4/6/8/10 instead of 1/2/3/4/5, that would reduce the gas dwellers average facility space advantage from 11% to 6%, and from 28% to 23% with "Advanced Storage Techniques".

Furthermore this will strengthen the AI, which cannot really cope with having e.g. only 1-3 tiny (size 1) planets in a system, and does not show sensible building behaviour there. With doubled the number of facility slots chances are better that it builds something it actually benefits from!