It's pure trigonometry.
You are trying to lift the coupler vertically to a point that is level, by pulling horizontally. As the angle between the A-frame and chains gets smaller, more and more force is required to do anything. The harder you pull horizontally, the closer you will get to to your target, but can never actually get there. I do not believe you can ever transfer enough weight to get all lost weight back on the front axle, which is the true goal of a WDH.
Conversely, a traditional WDH is trying to lift the coupler vertically...by actually lifting vertically. It's very simple, and does not fight against itself.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller