I have had very good results with two other powders in the .270 Win. and I hang onto the powder like a fine wine because they cannot be found anymore, otherwise I would have suggested WW785, and WMR powders. Great to work with and create small groups, and generate top velocity. If I was to start on a new powder for the .270 Winchester I would experiment with Magpro for 130/140 grain bullets. I agree with your earlier findings that 4350 is a good .270 powder.
I am locked into H4831 with 150 grain bullets because of good accuracy and very dead deer.