I notice that a lot of people use the Antonia74 recipe on this site. What is the difference between that one and the Wilton recipe? Does the cream of tartar in Antonia74 make a difference? If so, what is it?
I believe that the only differences are that Antonia74's RI has a bit more meringue powder in it than the Wilton recipe and it has Cream of Tartar.
Here is some information regarding Cream of Tartar:
"Cream of tartar is best known in our kitchens for helping stabilize and give more volume to beaten egg whites."
The meringue powders already contain cream of tartar, so I'm not sure why Antionia74's calls for more. I've only ever made RI following the directions on the can of merinuge powder (I use CK's not Wilton's) and it's always worked great for me.