Genius! Finally, a way I can use my six gravity nymphs effectiv.... oh wait... what gravity nymphs?
Joking aside, no one has six gravity nymphs, and it will probably be a long time before anyone does... so for a nymph deck to be feasible (for the time being), you should only have two or three nymphs max. So, replace some nymphs with a titan and perhaps a couple more regular black holes.