Luke and others:
I've taken the Disco with a set of 245/75 Michelin LTXs to TrueLine in San Diego; they did find deep flat spots on two of them. Shaved a bit from two "good" ones, and a lot off the bad ones - I guess I lost about 40-50% of useable thread. Still, better than losing two tires completely. Cost - $105 per four tires, including balancing outsourced to close-by Discount Tires (figure of reference: Discount Tires take about $20 per wheel for mounting & balancing).
I was pleased to see the little balance weights that replaced the old ones covering nearly 120 degrees of the wheel's arch. There's still a bit of vibration past 70mph, nothing out of ordinary. The tires are very quiet, and, with whatever thread they have left, seemed to do well in light sand and decomposed granite. Better than stock XPCs, and with absolutely no XPC "feature" whine on pavement.