Forks were made for stabbing...hence the prongs
Primarily i stab my food if i can, and if not, then scooping is applied. But the back of your fork? All i can say is WTF? Why in gods name would you waste your time trying to fit things on the BACK of your fork!? I mean, following that logic, why not use your spoon upside as well too?
As for the knife thing, Im a lefty, so fork in left hand, knife in the cutting hand. Cut off a few hunks of meat, and stab it. For scooping with a knife...use the knife to hold your prey in place, while chasing it down and scooping it up with the fork.