With slightly more case capacity, it may be easier to get the right charge delivered without getting a hernia...
I didn't mind reaming these guns. No way would I want to see that done to your vintage Super Grade...
Pick up a cheap Hornet rifle and ream it to K Hornet. It's a better case with a shoulder to headspace on, less case stretch, enough more capacity to more easily do what you're doing. And, you may find a 14 twist, which would also favor the 45 TSX load.
DF