Thanks for replies I'll reaching out individually too. The game is at growHive.io (I also own the .com as well, but these games seem to be .io now).
At the rate it's growing the current users will only be a tiny fraction of total so not concerned with upsetting them, but I'm very concerned with not making the experience crappy for anyone.
I seeded the traffic with my own domains and it's grown from there. I have a $1000 ad budget as well for the next few weeks but I'd prefer to work with someone with experience in ad campaigns instead of dumping it down the FB or Adwords holes.