Does injecting the SVG before everything, right after opening the <body> hinders page render performance?
Moving the injected SVG to the head solves the render issue, what would happen with page render performance, validation and compatibility (ie)?
PS: live example: http://codepen.io/rhawbert/pen/uAKfw
If you add the 'display:none' property it won't be in rendering tree any more, so it won't affect rendering performance at all. You can be concerned about bigger DOM size, but I think the difference is really noteless