This looks awesome!
You've inspired me to explore sewing, the different materials available for a saddle bag I can take on marathon adventures. I've seen some from Rocketfish and Revelate designs, but not quite custom! I'm thinking a 1.9oz silicone coated 70d nylon because it's about 20 dollars less per yard, available in many colors (not just white) and will weigh negligibly more than cuben fiber. Thank you very much for sharing your sewing experience with the online community, now I can order some cheap fabric to build a prototype and learn for myself.