A leftward curve sucks, i jave an upward so my dick looks shorter in mirror it so annoying, but i heard women like upward curve for g spot i think.
Tkto, yeah those stretches soind productive but maaaybe i'll do switching mod for stretches, one workout with basics, one day jai stretch.
As for advanced tehniques and those 30 secs, is because my hand are getting tired if i hold more than 30 secs.