Unless you are doing NHE or one of the other diets of that nature w/ no carbs and you are using the fat to aid in GH (NHE seems to recomend this) I would not recomend adding fat to your post workout shake. It will slow digestion and blunt insulin release at a time when you want the exact opposite.
1 tbsp with lunch & 1 tbsp. before bed with cottage cheese!
I also throw in some flax pills I got around to use them up, when they're gone it'll just be the 2 tbsp/day.