I use a homemade silnylon stuff sack as my bear bag. It has the standard square-shaped bottom.

I would like to make a slightly larger bag and I have two questions about design.

1. Would the the sack be stronger if instead of the standard square-shaped bottom I just sewed it like a pillow case? I think MLD uses this design on their bear bag.

2. Does adding a second seam add significant strength to the design of the sack?

1: I can't see why it should be any stronger - or weaker.

2: Does not add. May very slightly reduce, but only very slightly. Depends *far more* on the width of the seam and the number of lines of stitching.