I've been to Istanbul twice and on both occasions the boys were fairly average - maybe slightly above average but not large - and all cut. They were also either very hairy (yuck) or totally smooth. Someone told me that the young guys who are doing their military duty are shaved smooth at induction. I also found that most guys will fuck another guy at the hammam (most seem to be tops in other words) then leave you without a word to head home to their wives.