I need to set three PT 6x6s for a porch addition. I originally was going to hire it done but started looking at buying one or renting one. Local rental is a 5hp "cable" unit, 14" max, for $85/day, and a 13hp tow behind, 16" max, for $109. Reasonable to think I can do 3 holes 4 to 5' deep in a...