Singles are fine. Unless you can afford multiples. God of war zoa is like 70-90 pp. Even fresh cuts. When i get them i dip them in iodine and it helps the healing. I cant stand plugs either Moby I ussually just cut the bottom of the plug and glue it on the rock. This is my horrible Rack that i cant wait to rearrange the rock to glue everything but they have all been grown from 1 polyp.
Single polyps suck big time, but if you've got them from a reputable vendor who cares about their well-being then you should be fine. I bought the first release of SpaceMonsters and now I have on heck of a great colony. It's a risk you take with the hobby.
for me single polyps are the way to go, there usually all I buy for the fact that they are cheaper and grow into large colonies. Just have to make sure where ever you but them from gives them time to heal, they know how to correctly ship them, and you acclimate them correctly and find a good spot in your tank where they will thrive and ultimately grow!