Augie, that's a good idea to mount a ball on the back blade. I've put a receiver hitch on my bucket which I use for moving trailers around, including for launching my pond boat.
Would you mind posting a pic of how you attached the ball to the blade?
I share your concern about backing the truck into the water. I'll have to measure just how far my rear wheels will be submerged if I were to use the back blade orientation. As it is, my front tires get wet; In 4-wheel drive, I've always been able to back up out of the pond even if I have to lock the rear differential. Tractors seem to pull forward better than backward, so your orientation may have advantages.
BTW, that's quite the industrial-grade machine you have there. It looks like it could drag my 25-hp Japanese Ford all over the property!