Atticus isn't really my style, but I appreciate thats different, and a pretty cool name. And no the the end sound doesn't really put me off, infact I didn't really pick up on it ending like that until you asked... the way I say it, its not exactly at-ah-KISS... slightly more uh sounding maybe?
I'm not sure on nicknames, maybe kiss ;P... nah could call him Atty...