Agreed with Doge. Notches farther down the tube offer little value for the end user. Few would use the positions since it changes your cheek weld significantly for the sights. Kind of like how the fully collapsed position is pretty much only usable for storage. If you placed your additional notches closer to the end, say .75" apart, it would give the end user more fine adjustment for getting a proper length of pull for their body types, or adapt for vests/armor.
Glad to see you making these tubes for the market! I've installed hundreds of the OEM ones over the past decade. Looking forward to seeing how yours stack up to them.