More important than technique is the ability to toss the ball exactly where you want it...even if your arm can only raise to 45 degree angles above your head.
Accuracy is paramount.
I haven't chased a serve toss or caught a ball in over 35 years, and my arm doesn't ever point straight up, due to injuries to the shoulders.
Picture where you want the ball. Flat, top/slice, top, kick. Place it there.