FWIW;
Years back, even before I began loading a friends father-in-law who was a long time loader told a story about how he and a friend each bought Rem 700's from the same shop, the serial #'s where one digit apart, literally made along side one another.
The two guns needed a full .5 grain differance in charge to shoot the same group.
They brought them in and found the chamber size was a bit different. The only thing they could think of was that the chamber boring tool must have done it's last cutting on one, and a new hone was used for the next.
Point is, no two guns are alike.
You might just drive yerself nut's trying to get one load that's the best load for both guns,, I'm sure you can get close,, but maybe a little bit of difference will be needed for really sweet.