Taper and Hydration

My body tends to retain water well when I do something significant at least every 3 days.  I'm thinking that tapering for a week would have me peeing out whatever extra water I generally carry, thereby making race day hydration even more difficult.  Thoughts or strategies that work for you guys to get to the start line of a long race as hydrated as possible??

Drink sports drinks during your taper… the extra sodium should help you retain water.