Are you making sure the bead is off the ledge on the rim and sitting in the lower center of the rim when you have to muscle that last bit on? I get most of the tire on, going both directions from the valve. With 8-12" to go, I go back the valve, push it in and push the tire down into the center, then work the rest of the bead down as I go back tot he last 8-12". Usually then, that last bit isn't too hard.

You may well know all this already. There are tire/rim combinations that are very difficult even doing this. That VAR tool looks like a winner. If I were you, however, I would consider that tire/rim combo a no-no and look for another brand of tire that went on easier. (Murphy's Law. Flats happen. Tools get lost, stolen, borrowed, break. Or are sitting in the tool bag ready to be used; on one of my other bikes.)

Ben