I love the fact you mounted your chalices on live rock! Lots of people just leave them on frag disks for fragging. This gives them more of a natural beauty when they encrust in the form of the rock.
All of the above. They seem to grow in spurts and they seem to grow faster when they are supported. When they "chalice" , they tend to slow down in my opinion
I have not really noticed light as being the deciding factor on growth. On the other hand, I have no idea what makes them get growth spurts. bottom-line, its a mystery to me as most things in my tank.