I have been working up a hard tail 29er for gravel grinding. Back in the day I found semi-slicks so effective on my 26er that I gave away the knobbies.
Flat bars cause numbness in my wrists so I am using Ritchey Kyote bars with stubby barends mounted at the bends (about where brifter hoods would be). The bars are taped inboard of the levers.
Waiting on rim tape to come in the mail and then will mount up a pair of 700×50 GK SK+.
I went HT over FS for two main reasons— Simplicity and Cost. I am building it up out of mostly new parts but an older frame and air fork for under $1k.
Thanks for the great informative thread.