I've done the "Mexican match" ammo before for a friend. With the kinetic hammer it was easiest to break the sealant be pushing the bullet down into the case just a little bit with the seating die, then putting the round into the hammer. When the bullet popped out we dumped everything into a can and sorted out the bullets from the powder later.
We kept track of the powder and weighed it back into the cases from the powder measure.
I can't remember what bullets we used, but they were 125 grainers, and hit to the exact same point of impact as the fmj's. I don't remember if we were fussy about the OAL, but so long as it fed through my buddy's CZ rifle, we were happy