Some of the Iranian / C99 will finish as early as late August, early September. Couple years back, pulled 17 ounces from a stealthy one. Began harvesting it in late august. Decent haul for such a quick finish. No mold, Good sticky buds and fine smoke too.
Same pack of seeds also had a couple other girls that didn't produce as much and the smoke was okay, but nothing remarkable.
There is some size and potency variation in this cross, but you do get 11 seeds from Dr. Greenthumb usually, so they'll probably be something good in there...
No experience with the Iranian / G13.