I like to add them selfbows when the bow is in good tiller and still ~10-12# overweight, since you'll loose some poundage cleaning the limbs up afterwards. That leaves some wiggle room to make finall tiller adjustments, do the rough sanding to remove tool marks, and ease into the last few pounds.

Here's how I usually go about it:

http://home-and-garden.webshots.com/album/122889814mrjYrU