We have recently begun inspections for OSHA VPP at our facilities and have been shoring up material storage issues. We have 500,000+ sq ft facilities and employ both rack and floor-stacking for storage of grocery products. IMHO, there are no absolutes-other than setbacks for fire codes or mfg handling requirements. You need to develop policies to mitigate hazards and then train your employees, inspect to ensure comprehension and adherence to policy and administer retraining/corrective action when policies are not followed. Why I say there are no absolutes is that ultimately we train our employees that no matter what the policy states, they are ultimately responsible to ensure that the pallets are configured within the guidelines in a safe and secure manner. We have pallets triple-stacked in excess of 20'+, and the above program was completely acceptable to Cal OSHA. With respect to pallet-wrapping, we require all pallets above 12' to be wrapped , but then we also train the employee to wrap anything lower which is unstable, we don't allow our operators to use policy as an excuse for creating a hazard.
No matter how well crafted your programs are, if you have an inspector that wants to cite you they will under the General Duty Clause. A well though out and administered program will simply lessen that likelihood.