Ok, I looked at the tutorial at Diesel Giant and it could be either way but the official manufacturer way says the lower is the lock nut. Assuming I wanted to do it that way I guess I would turn the lower nut clockwise to loosen it from the upper nut?

Or maybe instead of holding one I should do both at the same time... top CCW and bottom CW and one of them will eventually loosen?

Odds are pretty good that they will both loosen at the same time.