I They definitely like to eat - my favorite coral to feed. Total pigs! Feed 1-2x a week. Mine do well on pellets and meaty foods.
My duncan colony is need of fragging as it will be growing into my frogspawn shortly. Little nervous to frag as I have seen/read that they are not simple to frag. Any tips?
Do they heal similar to hammers, torches, etc?
Hafta 20 bucks is a fair price. Ten dollars a head is pretty common but I have seen some LFS's charging 20 a head.
The "skin" may or may not grow onto the plug . Most of its growth will be the heads budding and branching out.
If you do not like the look of the plastic you could always cut it off and attach the duncan to a piece of LR or Dry Rock. If the heads are really close to the plug it might be best to wait till it branches out more so you do not damage the polyps.