well Bxing is okay, actually its not a bad way to make strains. unstable? no, not till you exceed a Bx2. a Bx3 is unstable, but gives you the highest chance of getting a plant closest to the original. if you want to BX again you would have to breed you bx3 male with the original chemd strain, or breed it with another Bx3 chemD but then you might start seeing problems.