Requesting advice on following: I'm attempting to install a Goalrilla in-ground basketball system. Mfg states concrete (reinforced with 4 rods) must be poured in a hole 16" wide and 48" deep. I struck ledge after 24" of digging, then jackhammered out 12-14" of rock. So, hole is now approx. 38" deep...about 10" short of the recommended depth. My hypothesis: A 36-38" deep concrete footing (with lower 14" surrounded by ledge) will provide the stability needed to prevent the system from leaning/tipping, as well as minimize vibrations at the backboard/hoop. What, if any, concerns should I have with this plan? I don't expect Charles Barkley to be dunking or hanging on the hoop, but should I be concerned that the plug could break above the ledge? Thanks, Dadof4.