Sara,
This may not be completely relevant to your situation, but I got a Reese 2 1/2 drop draw bar and put the ball in upside down. So the top of the ball is about 2 inches above the top of the coupler (with trailer level) when I back up to hitch. The weight of the trailer levels it out nearly perfectly on my rig. Your mileage may vary
. Note with my new WDH, a whole new ball and adjustable draw bar is used. I will no longer use my old draw bar and ball. So maybe you could rent a draw bar and hitch ball from U-Haul until you get your WDH installed. Hope that helps.
Mark