Been just reading this entire thread and really enjoyed the positive supportive banter and all the photos.
Only contribution I can make is if you have a 34-46 crankset consider going 11x40t on the cassette. I had the stock 32t max and even with 36t you may find it too big especially with any gear, particularly on gravel as the hills can just be that much steeper than any paved roads here in Canada.
Got the newer 11 speed Ultegra (105 now exists too) with clutch and it works up to 40t despite the shimano spec. XT cassette 11sp 11x40t,Fyi.
Thanks! Can't wait to see more builds.
Ps. Have an older rocky mountain hybrid with V brakes and lots of clearance that could make a great 650b 1x build someday... Heavy aluminum frame but heavy duty for sure!