Mounting Flush Heavy Duty Swivel Rod Holders to Seacraft

[RickBomba]

Hi Guys,
I want to mount rear heavy-duty Smith swivel flush mount rod holders to the rear of #^&#^&#^&#^&y's and my 21 foot Sea Craft CC. The only problem is the gunwale is not flat by the rear cleat, it's domed.

The rodholders are 15 degrees, and I have backing plates, so I get that I'd need to put in access ports to get at the adjuster screw and the bolts under the access ports.

I also know how to cut the hole with a hole saw and then make the angle cut so it sits flush.

My real question is how do I deal with the domed gunwale? Use a bigger hole saw and only do down a little bit?

I tried posting this on classic seacraft, but got no real help.

Any ideas would be appreciated. I'd like to do as little fiberglassing of the gunwale as possible after I'm done, to clean up my mess.

Thanks,
Rick