How to "Call" a ball not caught

[JPaco54]

It seems there are many mechanics that umps use for different circumstances. Are there not standards for mechanics? I thought there were and I thought I was applying them but sometimes I get confused when I read differing opinions on this forum.
1. Interference - Both hands up and vocal - Dead Ball
2. Obstruction - delayed dead ball - Left arm extended horizontally fist closed.
3. Caught ball - Out Signal - Vocal OUT (confused now, do we vocal CATCH)?
4. Dropped ball - No Signal - No vocal (Confused now - do we vocal NO CATCH? and Signal Safe).

I am assuming we must use some judgement on close calls for Catch No Catch...but I also believe that different mechanics cause confusion with players and coaches...Do we use signals as we feel comfortable with?

I also am assuming that different assoications may have some preferred mechanics that they insist on. I thought this umpiring stuff was easy?