Woohoo! I found one that had no replies yet (you guys over here have too many ringers! <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" /> )
45mm is correct. remove probably 10-12mm for hub and rotor thickness and you have ~35-33mm sticking out. Upsizes available are: 52, 66, 72, 100.
LINK
I also know a trick on installing up to 72mm rear studs without pulling the hubs if you need to know that.