I'm a big fan of just bolting the gunwales on at the ribs. When you need to do gunwale or side panel work you can have the gunwales off, intact, in about twenty minutes, and on again nearly as fast.
A friend asked me to replace her gunwales a few years back. What should gave been a two-day job took over a week, most of which was spent rebuilding the boat's side panels from the destruction ensuing from the gunwale removal.

Folks usually use blocks to separate the inner gunwale from the side of the boat, placed roughly where the ribs might have gone. This is where the bolts pass through.

No, I never have done that, but some might. Seems overkill to me.