I have looked over so many forums and threads to no avail, google has not helped much either.

I am getting back into building some diy style long john/bakfiets cargo bikes. I recently finished my jig table and am looking for some doner bikes. but my issue is what sized tubing i should get for my head tube. I plan on using 1 1/8 threadless headsets since i have a few laying around, but in the end im not picky. In the past i simply cut off the bottom cup and welded that to a sleaved head tube, but id rather not go that route again.

from what ive gathered i need to look for 1 1/2 tubing with a thickness of around .045.

then my question is (if that is indeed the right sized tubing) once the bike is welded up and done, ill obviously need to take it to a shop with a reamer and facer and get that done, right. then im good?