Either will generally get good results.
I have at times with some guns gotten slightly better accuracy with H4350 but not as good of velocity as H4831, which most times also provides excellent accuracy.
H4831 will usually shoot well under most any quality 130gr bullet that your gun likes.
One of the well known and widely used classic loads for the 270 Win is 60grs of H4831 under a 130gr bullet.
The 130gr Barnes TSX or TTSX in Win. cases, WLR primer & 60grs H4831 shoots very well in a couple of 270 Wins I currently have.
I would suggest starting down around 58.5grs and working your way up about .3grs at a time watching for pressure signs until you find a sweet accuracy spot your gun likes.
FWIW - I've had guns you could go up to higher charges with, but you need to find where your particular gun shows pressure.
Good luck,
Ted
