I dont have an optical comparator, however if I really wanted I could pull one apart and use a wire guage to work out the size, never thought of that.
I see cree state the bond pads fail before the bond wires.
I built a test jig with some leds, a xenon flash capacitor charged to 200v with only 500mOhm in series doesnt blow the led's, and the resulating flash is incredibly bright, the test ran a few hours without the led failing, but the fet switching the led did, not sure how many amps there was flowing, probably 25 to 50 or more for a short time.