Threaded or Threadless, decisions, decisions??

As some of you know, I bought a frame that I am building up as a travel bike. It has a 1 1/8" OD HT, which means it takes a 1" steerer tube. I have a choice of a 1" threaded or 1" threadless headset. As I understand it, the threaded will look nicer since it takes a quill stem, and since I like my bars high (same height as saddle) I will need to use a lot of spacers with a threadless, and need a shim to use a 1 1/8" stem, so it will look a little clunky. But as a travel bike I am worried that those pretty stems like the nitto technomic will be hard to pack since the bars don't unscrew easily (the quill stems that unscrew easily don't give me enough rise). Also, if someday I want to use this fork (its a custom 24" fork) with my other bike that takes a 1 1/8" steerer tube (1 1/4" OD HT) I can buy a chris king threadless headset that does that. I also read that threadless systems are lighter, but is that true if I don't cut my steerer tube to get max height? Also, since I am installing canti brakes, does anyone know it the front brake hanger will mount on either type of headset?

I've never actually used a threadless headset, so I don't really have the full picture here. Hopefully someone who has used both can give you some additional perspective.

Threaded headsets tend to loosen occasionally just from road vibration. Occasionally meaning that it might need a readjustment every year or two or three. I assume that threadless are less likely to do that.

As far as packing a bike with quill stem, it's not that hard. You pull out the quill and leave the bars attached. You can loosen the stem bolt and rotate the stem on the bars to make packing easier if necessary. When brake levers had long cables out the top, you could get away without disconnecting the brakes and just lash the bars onto the frame. With cable routing under the tape, you generally have to disconnect brakes (and gear cables for STI) in order to remove the quill. Oh, you have canti brakes. So you just disconnect one side of the bridge and you might get enough excess cable to avoid the disconnect. Maybe.

I was reading the Chris King headsets can adapt for either threaded or threadless use. They sell conversion kits.

Your choice ultimately depends on the steerer tube of your fork. Is the steerer tube threaded or threadless to begin with or do you have a choice there as well?

Your builder should be able to give you a good recommendation since you've got the two bikes to consider. I assume that as a custom fork it will have a steel steerer tube? Carbon steerer always have a max spacer height. Not sure about steel.

You can always start threadless and go threaded but not the other way since the steerer tube gets cut.

Threadless is lighter. Probably easier to find a greater variety of stems in different lengths and rises, and therefore play more with the fit of your bike. Threadless allows you to change stems without pulling the entire front end apart. I don't think the brake hanger cares which way you go. The shim looks just like a narrow silver spacers and belnds in with a silver Nitto stem.

You can always start threadless and go threaded but not the other way since the steerer tube gets cut.