Yes, I frag zoas by the same or a very similar method. I try to get as much sliver of live rock underneath the zoa mat to minimize a stress. I sometimes just crack or break up a rock rubble or a reef plug that zoanthids are attached to with a driver and a hammer and create a frag by cutting the connective tissue.
Really, there's nothing to it. Zoanthids and palythoa are very durable. You can simply tear their mat and glue a torn patch to a rubble or a reef plug and they do just fine. I recommend that you disinfect zoa frags with a quick dip in some coral dip solution just in case to avoid a bacterial infection. I normally don't lose any zoa frag as long as I keep the frags in an area with a steady water flow.
You can cut up just about any soft coral with a scissors and create a frag. They will attach themselves to rocks or plugs very quickly. The only thing that I had trouble with is a colt coral. It does not seem to attach to rocks very easily.
Tomoko