i just used the guidelines i found on line as to the amount in ounces needed of the "beads" per tire size, then used that figure to measure out the same amount in the air soft pellets.
i used a postal scale, put a cup on the pad, then zeroed out the cup. poured in the pellets until i got the correct amount, done.
rinse and repeat for the other three tires.
i had studded winter tires on the front, and i wore those things down to almost the wear bars and didn't have any problems with vibration of any kind.