I'm sort of in the camp of luck-neutral performance as a measure, so I'd say 81 pitch, 27 strikeouts would be perfect perfection.
I might say that Pedro's 17 K game against the Yankees on 9/10/99, with the only hit being a Chili Davis homer, was better than some perfect games. 98 game score, .623 WPA. 120 pitches, 19 swinging strikes, 29 strikes looking.
Compare that to Buerhle's perfect game. 6 Ks, 93 Game Score, .290 WPA, 116 pitches, 6 swinging strikes, 22 looking. Buerhle more or less needed a spectacular catch by Dewayne Wise and solid defense throughout in order to even be in this conversation.
Kerry Wood's 20K game was damn near perfection. 105 game score is the highest I've ever seen.
Edit: Yesterday was the 25th anniversary of Clemens first 20K game.