Setting up chamber, how far out to seat? pics

[Marine sniper]

I am sending my rifle to get re-reamed, these are the two bullets I would like to try first, 210 Berger and 240 Sierra (.30-.378 Weatherby). I put together two rounds for the gunsmith to set the chamber up around. This is a single shot action so overall length is not a concern.

How does this look, I "think" I should have the base of the boat tail at around the juntion of the neck ?

Any thoughts?

Thanks,

John