You seem to know your tastes well enough to not need any advice from me. You'll know there is something missing from your drobe the minute you don't want to wear anything in it
I wanted to address the issue of a fragrance collection feeling complete. I had this idea - that there was some amount of fragrance that is "enough" and I would know when I got to it. I tried to guess how much is "enough" and limit my collection to that number. Well, let me tell you - that number went from 6 to 12 to 20 and I now have 22 or 23 bottles. I don't think there is a limit. It's great that you pared down from 40 to 20. Maybe you have now determined that 40 is too much for you.
As for content rather than quantity - I had this idea that there are certain bases that need to be covered for this "complete" collection. You need a few office scents, a few evening scents, 1 or 2 suit scents, etc, etc. Then the summer/winter divide doubled all those numbers. Then I started looking at things from a fragrance familiy perspective. Should I own something mossy? Should I have a gourmand? Maybe I need a few classics?
Luckily, I'm over all that stuff now. Does that mean my collection feels complete? Not at all - but I think I have learned how and why to add and subtract from it. I don't really WANT my drobe to become static, but I also don't want it to grow out of control.
To bring things back around to my original point - you know you need to add something to your drobe when you want something that you don't have. I don't think there is anything you "should" have.