Body Filler over Laquer Primer?

Hey guys, is this a good idea or bad idea? I have stripped the Valiant to bare metal and have shot it with sanding primer only. I keep it in the garage at the moment so moisture through the sanding primer is kept to a minimum for the moment.
I am wondering is it a good or bad idea to put filler over the sanding primer that is there? Or should I sand it back off as I work each panel?
Thx guys.