Assuming the fork has a 1-1/8" straight steerer, that headset will work if the headtube is made for press-in headset cups. An EC44/28.6, EC44/30 will also work and give a greater stack height. Spacers go above the top cover of the headset and under the stem.

I have no idea what the best headtube length should be. Why not ask your frame builder?