Dixi,
Don't quite get your point here.The reason for having a Fin/Director is to spread the overall R/T burdon.For Fin to be working properly then you need 5 to 6 a/c on frequency at all time.He/She then just nails speeds,heading,spacing.But it will be a busy frequency when you are going for min vortex,or 3 miles.
Also by introducing reduced spacing,then there are more a/c in there,so R/T stays high.Best way is stick to standard R/T,listen out so nothing needs repeated,and change frequency WHEN TOLD.
When doing Fin here,I operate as you get an instruction once and I don't want to repeat it.You can lose separation very quickly with dosy pilots,or ones that want to do there own thing.
TCAS is not an ATC separation tool.Just to save your neck when we screw up!