Awesome stuff @Mr.Make thanks so much for hopping into the community and sharing this ‘cheat sheet’ with us. Super valuable stuff. 
The same goes for @Donald_Mitchell , of course. Thanks for letting us know how you go about working with the last day of month in Make. 
Oh and this is so true! It’s really interesting to see how different folks choose different approaches to certain concepts in Make 
Just FYI
On a similar note, there’s also this community post about scheduling your scenarios to run on the last day of the month.