I have three 270’s and they all love H4350. The fact that you have a lot of H4350 would weight heavily in my decision. Having to buy new/different powder for a new cartridge adds to the overall cost versus having an efficient powder supply that works across multiple cartridges.
search and see what you can find available in the gun you want or like. Then figure it out from there. All of those calibers are known to be easier to load for and components should be readily available.