How should I alert this 1D opening?
With the new ACBL Alert regulations (effective January 2021), the following seems correct:

You Pre-Alert your system, because of your 1C (not Natural, Forcing) and 1D (not Natural) openers. &quot;We play Precision&quot; should be fine, but you should probably prepare a slightly longer one if you want to be clear.  &quot;Our 1C is 16+, any distribution; 1D is 3+ except in very rare cases; 1NT is 11-15 and can include 4M5m22s.&quot;

You Alert 1C.  When they ask, you should be more clear than the Pre-Alert.

You Announce 1D &quot;could be zero&quot;.  Here is where, I agree, it gets difficult.  This is why I recommend the expanded Pre-Alert, because most &quot;could be 1&quot; and &quot;could be zero&quot; Precision 1Ds include things like (43)=1=5 and 4=4=0=5s (and put the 2D opener to better use).  If they ask, you can say that it's 3+ unless you're 6C-5M or better.  I tend to ask &quot;when could it be short&quot; and this is a great answer (for me)!
Of course, if they ask for a better description of 1D, you can come out with what you have above; but your agreement isn't that much different from a &quot;normal&quot; 3+ 1D (limited to 15) that you should feel a requirement to routinely explain it.

You Announce 1NT &quot;11-15&quot; as before.  Be prepared to explain (if asked, or at the end of the auction if you're declaring) that you put more hands into 1NT than &quot;normal&quot;, especially the 4M5m22s.  Again, if it doesn't take too much time, the Pre-Alert should handle that.