Hi bro, I think if u can keep birdnest and monti then your water parameter should be more or less ok. Should be able to try other kind of SPS like milli,...etc. I feel keeping them not so diffcult maintain the colour is the difficult part. Like my tank can maintain most of the blue and purple SPS but come to red then cannot liao.
Cedric place is a good place to go also. His frag all very stable and at best colour already, easier to start and maintain.