Oh yes. Sketching is definatly going to be the longest part. I spent about two or three hours looking at the sprites of the items and sketching them out onto graph paper and writing down all the colors down. Then I re-drew them onto more graph paper and spent at least two full nights figuring out how many squares of color were in each block...and on a couple I spent an hour figuring that out because I had counted wrong so my numbers didn't total up right and it took forever to figure out where I went wrong.
Nesting? I usually press my seams open.