You might find the following resources quite helpful.
Second Life Storage. A forum dedicated to DIY 18650 battery builds.
DIY Solar Forum: A forum dedicated to understanding and designing solar systems.
Electromotive Mods: Designer and manufacturer of e-bike, scooter, and other mobility applications.
https://lygte-info.dk: Batteries and equipment reviews with a wealth of info on various 18650s and associated equipment.