Piston to head clearancing

[Ross F-1]

I've heard about this and when the time came for a rebuild, I "clay'd" the clearance to see what would be required. (see below) The numbers are with a used head gasket torqued down.
I asked my machinist (who has done hundreds of mild-to-wild flatheads) what he thought about milling ~.070" off a head; his jaw literally dropped open! From what I've read here and elsewhere, I think my numbers are pretty common for uncut heads.