Just got my Road Hawg today and I'm going to drill it up with a stacked leverage layout.  The ball specs are 15.4 pounds.  3" pin and 3 oz Top weight.  My span is 4 1/8" and I plan on drilling a 1 1/4" thumb hole 2 3/4" deep.  Am I going to need a weight hole, and if so where should I put it to maximize backend reaction?  How deep should I drill the fingers?  I'm asking because I don't currently have a scale to check these measurements.  Thanks in advance for your response.
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Shane Soule