Walker: .457 or .454 round ball, probably No. 11 percussion caps. Cap size is a crap shoot, however, depending on when the gun was made. If the No. 11's are too loose, go with No. 10's; they're not terribly expensive. Recommend 40 to 45 gr FFFg black powder, although you can easily use up to 50 gr with no problems. I use a lubed felt wad over the powder and under the ball in lieu of grease as a chamber sealant.
Pocket Revolver: .320 round ball (same as 00 buckshot pellet), probably No. 10 caps (see above discussion about caps). Try 15 gr FFFg black powder with the lubed felt wad.