1. Dunno- not familiar
2. I use all the nosler bullets except the 130 ET. The lengths vary but they all shoot under moa. The 160 PT which is rather long comes close to moa. I never felt like bullet length was a factor. Seating depth is the key for me.
3 The sierra 110 spitzer is .945.
NOTE; ya know what they say. If your .270 don,t like H-4831 the barrel is bent. I,ve used alot of it. It works. IMR-4831 is also very good in my .270,s