I climbed the South Teton solo via the Northwest Couloir back in June. I started from the car at about 2 AM and was on the summit by 9 AM. The clouds had not burned off yet and were streaming off the Cathedral group in beauteful ways. The climb was covered in snow from Garnet Canyon to the top, and the wind was quite intense in some places. I was the only person on the mountain that day which was kinda cool.
Didn't have it in me to double the Middle and South, but I came back a week after climbing the SW Couloir on the Middle to climb the NW Couloir here on the South. Great route and being late season, I was able to avoid snow the entire way.