[oldE]

Originally Posted by wdfifteen

+1
Don't make your life so hard. Drywall up to the sheathing, drywall down from the ceiling to lap over it. Finish it with a piece of J-trim, and get on with your life.

Phillips Manufacturing Company 8 ft. x 5/8 in. Vinyl J Trim (50-Pack)-JT6VYL 8 at The Home Depot

This, but I would probably cut the sheathing as close as I could with the circular saw first. That would leave a piece about 1.5" wide sticking down. Once you strap the joists and put drywall up there a piece of cove will cover the small edge of sheathing.

Best
Les