To further muck up the waters, a little math on neutral lines. If your truck has a high center of gravity, or higher than the average door car, then the neutral line will be steeper. Taking camshaft height as a guestimate of c. g., Say 28 inch? If your wheel base is 120 inch, and ladderbars are 30 inch from axle center to front pivot, then the neutral line at the front ladderbar hole would be a percentage of the wheelbase . Ladderbar length (30 in) devided by wheelbase (120?) equals . 25 of the wheelbase times the actual c. g. Of 30 inch. So that would be . 25 x 28, or 7 inchs off the ground. If my calcs are close, then IMHO I would place the front ladderbar mount with the bottom hole at 6 inch off the ground or maybe 6.5.
Since you will most likely be nose heavy, you will need to have rise. How much can only be determined by power, and the tires you run.
Last thought, consider boxing part of the frame rails, from the ladderbar mount forward maybe a foot or so?