I think the best way to find a fair game for both sides are people you played against in a tournament. Since you were not gambling at the time, just trying to win a match you have a pretty good idea of how you match up.
Not always, I know of an individual that entered the U.S. Open in 1999 & proceeded to go 2 and out intentionally all the while playing it up to everyone he was dead $. Then this individual ventured into Q-Masters in the wee hours one night flashing cash and negotiated a healthy spot against a particular Filipino player with a contingent of backers who made him freeze up 5 dimes to get the spot he wanted which he did, he then proceeded to rob them of 20 dimes, adjusting the game twice along the way. Several days later he barked mercilessly at an well known American player at the Convention Center after this player finished his match. A game was negotiated & arranged to be played at a local individuals home who had a pristine GCIII, a friend of the well known American player & he proceeded to rob that player of 32 dimes adjusting 4 times. All in all he had a couple grand in expenses for his hotel, entry fee & food. Once expenses deducted he rolled out of town with 49 large. Just because someone plays a particular way in a tournament doesn't mean that's his speed. Names of victims and giant killer left out to protect those that were robbed & the robber.