Achieving Consistency with Royal Icing

I wish I could remember where I got my recipe from but I can't. I've looked and looked and I don't know where it came from. I use 5 TBSP meringue powder with 3/4 teaspoon cream of tartar. Mix that in the bowl of your mixer for about 30 seconds. Add 6oz (3/4 cup) of water. Add to mixer bowl and mix until most of the lumps are gone. SIFT 2 pounds of powdered sugar (sometimes I even sift it two times). I dump the whole thing in all at once. Mix on med/low speed and add 2 TBSP clear corn syrup, 1 tsp glyerin and 2 tsp whatever flavor extract you choose. If you use the brown vanilla you can add some white Americolor gel to get it back to white icing. you need to mix this for about 10-12 minutes, never going over medium speed. You don't want to incorporate too much air. Air in icing is NOT your friend. Mix until you get nice firm peaks and it loses it's sheen. I've had great success with this recipe. Just keep in mind that if you want to make flowers like roses, this icing is too soft for those. You'd need to use a recipe with no corn syrup or glycerin. I hope this is some help. Good luck and let me know if you have any questions.