Soft lead .001-.002 over lands depending on powder/fouling

Jacketed is a whole other ball game. If lands are .451 lets say. You dont want larger than .4513. A .4515 WONT go down without a hammer. Best to do it by feel. Keep sizing down until you can start it with your fingers. Once the bullet can go in without busting your knuckles it might be enough. If it takes 2 hands to load without a ton of effort on your rod its a good start. If shooting real black or Triple7 you can get by with the least amount needed to keep the bullet seated on the powder. BH209 is better with a bit more resistance.

Parker Ballistic Extreme is .4515 and the jacket is thin. They size like butter. I think the other Parkers are .452. I would suggest getting Fury Custom bullets instead. Jackets are .015 and bonded. Plus they are cheaper than Parker.
https://www.furycustombullets.com/pr...oader-bullets/