Ok, never built a bare frame, so I have no clue on this.
Have: GTB frame. nothing else.

What dictates which headset/fork/stem I can use? (concerning size and also threaded v threadless)
I kinda need threadless, cause i want to switch bars without untaping often (removeable faceplate).
What makes a bike 1in vs 1 1/8... is it frame, or headset/fork?
Any suggestions for a carbon, with brake hole, track geo. fork?