I have wired over 5 acres of production greenhouse. In Ohio where I did it, it was agricultural and not subject to inspection.
The inspector didn't even want to discuss methods.
I have seen RNC used and it turns into a terrible mess in a few years. The temperature swings make it expand and contract until it pops out of straps and busts fittings. If the greenhouse is unused and the heating and ventilating systems are shut down an 80 degree swing is easily possible.
Also the condensaion that occurs will fill any watertight raceway until the devices are swimming.
The best job I feel is done with EMT and set screw fitting to let the moisture out.
I have run EMT following the curved portions of the structures pretty sucessfully. Try using small bends at intervals and minis as straps.
Any tie wraps or T-stat/Low voltage wiring needs to be UV resistant or it will be toast in a couple years.
If it is a commercial operation the oxidation from the pesticides and fertilizers also will hasten the degradation.
Good Luck
