I don't ever go all the way down to minimum rifle load data any more!
For any new to me cartridge, I use to reload a ladder in duplicates starting at the book minimum for each potential powder I wanted to test.
Some years ago I ran into the case not completely sealing at the min load.
I think your right on the correct starting point !!!
I mean you won't be wrong with a 25-06 to 7 mag,
but a 270 Win is the standard you should use judge the others.
A 25-06 will do most everything a 270W will do with 10 gr less bullet wt.
& a 270W will do most every thing a 7M will do with 10...
You got a nice rifle there!
I like Pre-64 Model 70 Winchesters.
Got 2 of'em - A 1939 and a 1942.
Both will still shoot 1/2" or better groups at 100 yards.
But they are the fussiest rifles I have when it comes to
either factory ammo or my handloads.
So keep experimenting.
I know my 2...
I'm beginning to like the idea of a 25-06.
Got a couple of 270s. Thought the 25-06 was too close.
Don't have one - never paid it much attention.
Until I helped a friend get his new 25-06 sighted in 3 years ago.
He's killed several deer with it since - all one shot kills...