threadless headset hissy fit
 

quick and simple, within reason, does it matter how tight a threadless headset is set as long as theres no play?

Yes it matters. The bearings will wear prematurely if you get it too tight-

+1

It wants to be tight enough as to not have any play yet lose enough as not to bind. In practical terms that window usually translates to about 1/4 to 1/2 turn of the wrench.

+1 it's like getting a shower just the right temperature. 1/4 turn too much and you're in trouble