Stay away from insulin. I don't give a fuck what some people on this site say. IVE PERSONALLY SEEN IT RUIN MORE THAN ONE PHYSIQUE
I agree, I would never touch slin if I had your look.
I use 5iu post workout right now because I don't look like you, and it is hard to ruin a blocky, shit physique like mine, lol.
Seriously, I would be hesitant to change anything, whatever you are doing is working incredibly well.