And then there were two

 The sun shone and the wind blew making Bill's transport of the 4x8 sheets to the wall like wind sailing.  We did get the second wall done and as he was starting to sheet the first wall, he found it wasn't square-- at about halfway (24 feet), the 4x8 OSB (oriented strand-board) was not laying square on the studs. So he measured and remeasured and determined the wall was out of square by 3/4".  He then measured and remeasured the 2nd wall and found it was out of square by 1/2".  So the frogging began (frogging being a quilting term for redoing your work -- rip-it, rip-it). The good news was he only had to frog half of each wall. So while he used the crowbar to take nails out, reposition and re-nail, I remeasured the blocking on the first wall and cut and fitted as needed.  Since I hadn't done the blocking on the second wall yet, I measured and pocket-holed those pieces which took up the rest of the day.  At 5:49 we were both done, cleaned up and were able to free the dogs from their imprisonment in the 5th wheel.  At around 5:30 we could hear Cricket screeching for her release as she could see us working up above.

After all the re-do, Bill got the first wall on the left (west) sheeted (the rest of the sheeting to happen when the walls are erected) while I did the blocking on the east wall.