I have gotten in the habit of manually typing "counters add 35 assassin begin" and "counters add 50 assassin end" so I can tell you that the window seems accurate to me. I would also like to have mafia add the counters for me automatically to save me from RSI.
The window counters should be added (after pre-existing counters are removed) whenever the following monsters are encountered:
- Gorgolok, the Infernal Seal
- Stella, the Turtle Poacher
- Spaghetti Elemental
- Lumpy, the Sinister Sauceblob
- The Spirit of New Wave
- Somerset Lopez, Dread Mariachi
- menacing thug
- Mob Penguin hitman
- hunting seal
- turtle trapper
- evil spaghetti cult assassin
- béarnaise zombie
- flock of seagulls
- mariachi bandolero
Additionally, the following monsters should cancel an existing counter for "Nemesis Assassin Window End" but not trigger a new window, since they are the last assassin:
- Argarggagarg the Dire Hellseal
- Safari Jack, Small-Game Hunter
- Yakisoba the Executioner
- Heimandatz, Nacho Golem
- Jocko Homo
- The Mariachi With No Name
Erich, it is generally considered a good idea to provide the devs with all the necessary information to add a feature you want. They are simply less likely to implement something if they have to look it up on the wiki.