4895 and 4064 are extruded powders. The IMR versions which I use aren't the easiest to meter, though with practice they aren't a problem. I believe Hodgdon 4064 and 4895 have shorter powder grains and should be easier to meter, but I don't use them.

For COL, you need to measure to see if the bullet comes close to the lands. There are a few different ways to do this, but I won't go into the details- try seating a bullet in a resized (empty) case so that the base of the bullet is .300" deep. chamber the round, if you feel resistance from the bullet hitting the lands in the barrel, reseat the bullet so that it is .308" deep, and try again.

If the bullet touches the lands at either point, you will want to measure how far you can seat the bullet out before it hits- reason to start at .300 is to make sure you have some safety margin instead of starting with a .308 depth. If it still touches with a .308 depth, you can adjust the bullet seating depth so its closer to the lands, though I wouldn't go any closer than .020" unless you have a high qulaity barrel on it that was carefully installed and the chamber was cut very carefully and the freebore in front of the chamber was cut very uniform and square.

If the bullet doesn't touch at either point- seat your bullets to .308" deep, or whatever is the maximum length that will function in your magazine- whichever gives a shorter COL.

Seating bullets shallower than its diameter to get you closer to the rifling won't give you any better results- the possibility of the bullet being knocked off center easily and a lack of neck tension more than destroy any potential accuracy gains.