Found this handy post outlining the the correct format for creating a URL to render a SSRS report hosted in SharePoint integrated mode.
Very handy for creating Go To URL Actions, speaking of which if you want to open your report in a new window check out the post below.
So it turns out that refreshing all reports on a dashboard may not provide you with the desired user experience; Content Editor to the rescue.
Add a Content Editor Control web part to your Web Page
First find the ID of the Refresh Button on on the SSRS webpart tool bar of the report to be refreshed; I used IE Developer tools to find the ID.
Once you have the ID, add the following script to the content Editor control and every 60 seconds the report gets refreshed.
var btn = document.getElementById(“ID Goes Here“);