I had tried that to no avail.
What bothered me is that it would start full screen, then get small. I think I have it working now -- I'm using a shareware program called Launch Later LaunchLater
which is supposed to make Windows launch faster, but unlike Startup folders and Task Scheduler, it allows me to specify a delay. A delay of 1 min 30 seconds seems to give Windows start up enough time to finish what it is doing and not steal the "foreground" back.
Interestingly with flash, both /r and /maximize don't run the flash "movie" I need, they pop open an Adobe Flash window with nothing it in.