I'd load that same bullet but work it up to max charge.
It's not hard to correct for 6" low anyway but why hunt with a minimum charge?
A 300 yard shot is 8 clicks up or a slight hold-over.
JBM Ballistics says a 168gr Berger at 3,100 from a 300WinMag 1.5" high at 100 would be 4.9 low at 300, so I don't see what you'd be gaining.
I'd work that .257 up to an accurate, near max load and sight it in about 2" high at 100. A 100gr Nosler Partition at 3,200 2" high at 100 is only 3.5 low at 300.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.