Do you have a picture of the feeders? I think your scrub may be a tad larger than my 5.5 ft male. I feed him mostly mediums but he's eaten a couple of large rats as well. He looks a little plump for a few days but other than that there's no issues. Your boa is a pretty good size critter too. I would think a medium rat wouldn't be an issue but I prefer to feed my boas smaller meals than I usually feed my similarly sized pythons.
@ wnateg- That's a gorgeous scrub and that video shows how easily they can take down larger prey. I would never feed my snakes processed food though.