A little about me first, I'm turning 16 this year, 65kg about 1.7m tall... Swing speed about 105mph, classic in to out swing with a nice subtle draw.
I've been gaming the R11J SR flex stock shaft for about 4 months now, its worked beautifully for me. The feel is good, easy to control but it might be a little on the light side since its asian spec-ed. however, you lose the ability to tune weights so the club is going to be permanently draw biased. Off center hits usually still end up going relatively straight with a slight loss of distance, centered hits have a very penetrating ball flight and a good amount of spin at about 2400rpm or so. Try them for yourself, what works for me might not for you.