Just thought I'd post an update, before the new year. Been working on more efficient movements this offseason. Son is 13/8th grader. Thought this angle was useful to show arm action.
Many thanks to Lantz Wheeler/BaseballThinkTank (both through the pitchingmastermind system and in person instruction...he's a truly excellent dude and coach, and the program is extremely detailed and helpful...highly recommended).
Also, he's been working with Kyle's/Driveline weighted ball drills, 2lb ball lawnmower drill has been particularly helpful for arm path efficiency.
Obviously still a work in progress...still working on improving glove side and lower half use.