Connors also has most lifetime wins (1243), a number that will likely not be reached by another player anytime soon. Federer at 868 wins is not going to catch him. So quite an accomplishment. And I believe Lendl is second in total wins. So for me, Connors and Lendl are 1 and 2. Forget winning percentage, although Lendl's is very high.
So you're giving the same weight to grand slam and neighbourhood tournament wins?