Actually, he cannot learn Struggle (nor Chatter, but that is almost a moot point). Just thought I would say that so people do not get confused. source
I did this with Murkrow and Smeargle. It isn't so bad if you can do it in a double battle the first time you fight a duo, since their Pokemon won't be as strong.
P.S.- Great guide, I love how much you praise Smeargle. I will be featuring this on my Team Page's Helpful Links section.
EDIT: By the way, catela, you may want to look into putting Odor Sleuth in the Utility Section for Smeargle. This move allows him to hit Ghost Pokemon with False Swipe, Pay Day etc.