Once the selection's complete, you can go back into the regular RGB channel, then back into layers. Load your finished selection. Here it's shown closeup, quickmask on. With the selection on (quickmask off) and the move tool selected, you can now nudge your picture into sync using the left or right arrow keys...
And voila, the finished product. No more blurry edges!

 

Questions? Comments?
e-mail: tom@ahoymatey.com