All the powders you've listed should work good with a mid weight bullet like the 168 and with a shorter barrel like the carbine.  I don't know a thing about MR-2000 however.  I'm not finding it on the burn rate charts I often use.  I did however find a paragraph saying it was comparable to RL15, so same neighborhood as the others you've listed with 4895 being a bit faster than the others.  I'd try Varget first, lots of fellows dote on the accuracy they get with the powder.  About all the cast bullet benchrest shooters up in MI were using Varget a few years back.