your build is looking good so far and welcome to the 41. you should check with pedal force about the derailleur clamp size to make sure you get the right one but i would guess it is 34.9 if you seat post is 31.6.

you could also use one of these is you want to use a braze on front derailleur still. not to mention you can get them in any color you want and they are light and cheap.
http://fairwheelbikes.com/kcnc-front...mp-p-2943.html

hope you are not in a hurry to build that bike though since it will take a while to get the soul wheels but they are worth the wait. if you are in a hurry though there are plenty of other good wheels you can get cheap as well and have them with in a week.