I just finished building my second sewing / MYOG project (the first being a prototype bag). A pair of frame-less bags for myself and my brothers GR10 hike this summer. I can say I am very pleased with them as they turned out better than expected :)
Under the following link you can read a detailed description and see a lot more pictures of the sewing process for this backpack: https://redd.it/8co09q
Warmest,
Conor