Steve,
An excellent resolution test for a 10X bino (and the observer) is afforded by the 14" separation, equal-brightness pair 100 Herculis. If that one's too tough, the somewhat wider pair of 8 Lacertae (22") would be a good next target. Naturally, the bino needs to be steadily mounted. At 10X, each pair would subtend apparent separations of 1.4 and 2.2 arcminutes, respectively. The human eye's limit of resolution seems to be commonly stated as being 2 to 2.5 arcminutes.

(Epsilon Lyrae is of naked-eye separation, and nu Draconis, with its 1 arcminute separation, is considered resolvable with an opera glass.)