Pairs are always somewhere around 50/50 with overcards, but they aren't always slight favourites. Many suited and/or connected overcards are actually slightly stronger headsup. For example, from twodimes.net:
cards win %win lose %lose tie %tie EV
9d 8d 894863 52.26 782248 45.68 35193 2.06 0.533
2d 2h 782248 45.68 894863 52.26 35193 2.06 0.467
And, like you said, QTo vs 22:
cards win %win lose %lose tie %tie EV
Td Qh 863394 50.42 828520 48.39 20390 1.19 0.510
2d 2h 828520 48.39 863394 50.42 20390 1.19 0.490
Note that if the QT doesn't cover 22's suits then it's 0.501 vs 0.499.
As for examining heads up situations, I would recommend
twodimes.