You can check the FPS with ALT+F. A list of shortcuts is available in the config app.
Provided your Skyrim SE is updated to the latest version, DirectVR FOV is applied without scanning, which is the most important thing. Not ideal, but not a major issue if the rotation scan fails. if head tracking feels off, adjust the head tracking sensitivity in the vorpX menu.
In general I would recommend to use the original Skyrim unless you absolutely can’t live without the new, more saturated color scheme. The original Skyrim on most systems runs better with vorpX.