I for one would not quibble over the price of the Foz. I was trying to find out from owners how it works is all, so I could decide for myself whether it works as I would like it to do. I want my $250-instrument to take me where I want to go. Setting by eye would be OK, if you knew for sure that the transducing mechanism inside the cartridge body was completely squared away with respect to itself and to the cartridge body.
Setting VTF by ear could get one in a lot of trouble. Obviously you need to have a known measured starting point else you may crush your cantilever or damage an LP.