I do not. I wish I did actually. And I have been looking for another one to build this winter actually. I would skip the 550 on your ski timeline and go straight to an SJ. My RN is my favorite ski by far and I wish I would have bought it sooner.
I would suggest trying to shorten the pole on the 300sx so you can distribute your weight better. So it can plain off and be a little more fun from the get go, along with some 0* bars. The bars are just my personal preference, lots of different opinions on what bar setup to run.
The stock hand pole is aluminum so it can be shortened easily. I was also a lot heavier @ 16 when I had mine so you might be ok with out doing it