Ya, difference is you are reputedly an excellent skier. Anyone that size who isn't definately could not ride 190 gots effectively. Besides, 5,7 is not tiny. I meant if he was like less than 5,5 in which case something like a scratch bc 171 or 169 sv would be better.
Anyways, at 5,9 and 80kgs he's identical size and possibly level of skiing as me. 183 Gots will suit you down to the ground for versatility but if you prefer mach 10 super g turns then go for the 190. Also check out the armada ANt 191 for the same thing. You didn't say whether or not you were looking for any BC freestyle attributes. If you were maybe look into the Made'n AK but be warned its much softer!