It looks cool, but I'd rather use completely independent random passwords. You seem like a nice person, but I don't trust you you to have gotten your crypto totally right. Someday I'll describe how a massive flaw in my understanding of gpg and pass let me recover from loosing my gpg key.

One small comment: the password I remember is the password I type, or I run into issues. If the sentence has "the" and plurals, so will the password.

(This password I generated was only used as a master and for a handful of key services)