The Visitor API file is included in both Tag templates. The templates are designed to check for the VisitorApi.js file in cache before calling it. So, if the Target Tag calls the Visitor API, then the Analytics Tag should use the same file instead of calling it again. What both you and Jonathan have described is a common implementation. Was there something specific you wanted to do?
Yes. I need VisitorAPI fire before mbox.js which is currently deployed via utag.sync.js.
If I use built-in VisitorAPI I don't get data into Target Standard as AppMeasurement fires in my case after mbox.js.