From NZ.
150+ gets very laggy for me. Though it's a bit worse than that might sound - recently I've been noticing an extreme sort of lag above and beyond the usual, with rubber-banding and major issues with clicks not registering at all. Even before that, highpop was unplayable for me as a direct combat role. Unless I was feeling especially indifferent towards accidentally shooting people in the back, that is.
I have a few suggestions up on the git for lag-reduction options - periodically deleting bloodstains, gibs, rubbish items etc, which IMO might become necessary sooner rather than later.
One issue with the proposal for expanding dropships, medbay etc - what about lowpop? There aren't always enough people on at some hours to make full use of existing facilities, and in expanded ones they'd rattle around like a dropped HEFA in Briefing.