I'm not a big fan of the basic sugar cookies dough recipes, finding the biscuit not very tasty and quite hard (even though I added lime zest) so I would recommend using the shortbread recipe from my first post. It doesn't rise so you will get a cookie that can be easily iced. I used parchment/baking paper cones to pipe my icing as I think they give the best hold and you can have different ones for colours. They are also of course cheap to make and don't require cleaning out when you are done- one of my pet peeves!
Here are the pics.