I’ve also wondered if there was a reason Tormach didn’t didn’t make them in the smaller sizes??
I’ve had relatively good experiences with the 3/16in size, but of the 3 pieces of 1/8in “ATC Compatible” tool holders, all of them have had OD’s too large to fit the forks in the ATC. I informed the folks at iCarbide about this and waited a couple of months, bought another one and found the same thing.