Yet another do-it-all (mostly) biek

Have had some discussions with Hallett and Woodrup. Kevin Sayles at Woodrup commented:

At 6' 5" I'm thinking 650b wheels might look 'small' on a frame sized to fit you?... there are more tyre choices available now for 700c wheels, I've recently built a frame to take 700 x 45 tyres, anyhow it's perhaps something you should consider, but of course if you are set on 650b then no problem.... other than I'm informed that obtaining no-disc 650b rims are getting very difficult and that's before the current issues the cycle trade has experienced following Covid etc.

Should I just be looking at a 700C frame with big clearances for cushy tyres, and if so, how big (with room for guards)? What #supple all-road 700c tyres are there? Looks like Marathon supremes come in 40mm, Gravel Kings in 38 and 43mm , Rene Herse in 38 and 44mm.