Drain hole locations, rocker panel, undercarriage

Where are the drain holes for the rocker panels and other major structural frame parts, undercarriage? This is for a 2017 Corolla iM hatchback.

I had Corrosion Free rust proofing applied to my car and wanted to know where I can spray extra/touchups later with the spray can of the stuff from CT. I didn’t see any holes drilled, so they must have sprayed it using some drain holes in the rocker panels I would think.