Have enjoyed building and riding my fixie conversion (and on a trackstand* it makes a great stationary bike too). I followed Sheldon Brown's loosen-the-chainring-bolts-and-tap-the-chain routine for getting the chainring concentric but, try as I might, I can't get the chain tension totally even - better, yes, but not perfect. I know, futz with how tight or loose the bolts are, etc. But still...
So, how "perfect" does it have to be? Hints and tips? Yes, the chainring itself is fine.
I'd just ask Sheldon but with his recent health issues he has bigger things to worry about I'm sure.
*Edit: I meant a trainer.