Mark.
I don’t like drilling holes anywhere either. I get a bit nervous when I see someone heading to their boat with drill and bits in hand especially if the boat is in the water. The bulwark and deck mounted stanchions are by far the best. When mounting to the deck you are not really drilling into the deck and core, just into the covering boards and deck and hull flange. Make sure you are clear of any of the plugged bolts that hold the covering boards in place. It will be hard to tell where the hull flange to deck flange bolts are under the covering boards. Our stanchion bases are through bolted and not held in with screws. The flange bolts have sort of pattern so perhaps you can see from the underside where they would not pose a problem in drilling and place your bases in a place where there are no bolts.After drilling be sure to seal the hole in the wood. I usually try to coat the sides of the drilled hole with epoxy and bed with caulking. A lot of care here will pay off in having no leaks below. Best of luck.
Bob & Lois
BCC Jolie Brise