The pic I posted was just for the colour scheme. Adam coloured in the generic picture. My frame has not arrived yet but should be here with me in Europe mid-April. So I cannot comment on the build quality just yet. I shall when it has arrived. It is an expermiment for me too, and I decided to take the risk, if it is one.
So as it is a generic pic, the bottle mount cannot be seen. I just asked for it to be the same like on the genesis datum: http://www.genesisbikes.co.uk/bikes/adventure/frames/datum-frameset.
I asked Adam whether it might be an issue re stability of the frame, drilling an extra two holes in the down-tube. He said, it should not and I believe him as the downtubes are usually the thickest. So as for the top tube, I don't know but presumably you could set smaller screws also? You can tell I am no expert. I shall submit close-up pics in this forum when the frame is here.
So 47mm/650b are not wide enough for you? But you're right. It seems a challenge to find that variety in 650b. And thank you for the feedback re BB86. I think they're great and actually aesthetically more pleasing. Just installing them will be the challenge.
Thanks platypus. I've got the mounts for the 3rd bottle cage on my Niner. I don't use them now but think it would be useful for bikepacking.
47mm is likely wide enough but more is always good. I was just comparing it to the 2.1" on the U.P. We do have areas of soft, deep sand around here where wider could be useful. I like riding singletrack too. And, as noted, there aren't many knobby tires currently available in that width.
Wheels Manufacturing has a very nice consumer level tool for installing a BB86 as well as other common bottom bracket sizes.