I had two that I placed on frag disks, mid tank. They grow like crazy-5-10 heads every other week lol but theyre babies.
I had 3 that were placed on regular frag plugs and they grow babies on the side of the original skeleton (bandsaw was used to cut colony). Theyre placed in mid/top tank on a frag rack.
Once they grow over the frag plug, Ill drill a small hole in a piece of live rock (probably mid/top tank) and just fit them to that.
The whole goal-for me anyway-was to get them to grow fast. To do that you need them to spread without having the build a skeleton, ie using the rock/plug as a surrogate skeleton. Make sense?
As long as they can spread horizontally without having to build a skeleton to get to the next flat area, they will spread fast.
Hope this helps.