Best seam for bear bag

[u/QuietTurtleSprinting]

I am planning on making my own bear bag using something like Ultra 400 or 800. The bag would be a draw string (UHMWPE rope) closure similar to Ursak. There would be one seam down the length of the bag and one closing the bottom.

My question is, what would the strongest seam be? My first thought is a flat felled seam but I don't think it's possible to sew a flat felled seam on a cylinder without specialized equipment. I have a simple domestic machine. Are there any other strong seams that would be suitable? French seam maybe? Or maybe someone knows a secret method of sewing a flat felled seam on a cylinder?