I trimmed the excess batting and ripstop along the side seam.
Strap - I used ripstop for the strap to keep the carrier lightweight. I cut (2) 3” wide and 40.5” wide pieces of ripstop fabric. I serged these two long pieces of fabric together along one 3” end for one long strap. I stitched this serged seam flat for added strength. I folded the long edge of the strap in half (right side facing) and serged along each of the two edges (along the fold and raw edges).
I measured the strap on my body and ended up with a 72” long strap with 5” folded under at each of the two ends of the fabric. I stitched a box stitch to reinforce the strap ends to the outer bag.
For the drawstring detail I followed the same steps as mentioned in the stuff sack project.
I love this bag and am super excited to use it this fall! The lightweight and water resistant elements with the fabric are so helpful for this water bottle carrier application.