The Vega lites are held in with a two piece rubber weatherstrip / locking strip combination.

I know this is not offshore quality construction, but it has worked well on most Vegas for almost 40 years.
Most of the Vegas I've heard about that went offshore were converted to an all-metal window frame bolted to the cabin sides. I believe "Berserk", the Vega that cruised from Scandinavia to the Antarctic, had stock windows and suffered a blow-out in a storm in the South Atlantic with almost disastrous consequences.
But for coastal cruising I'm happy with the status quo.
Mockup of placement, exterior:

Mockup of placement, interior:

(The size of the cut-out hole is smaller than the inside line on the mockups.)
These lites will give me good forward visibility while behind the dodger, or down below in the main cabin.
The original lites are made from 1/4" tempered glass. As the forward face of the cabin has a curve to it I'm going to use 1/4" Lexan, and give it a slight bend. The finished height of these lites is less than 3", so the Lexan should be sufficiently strong.
I guess why I'm posting this is that I secretly hope someone will point out a major flaw in my design before I get out the jigsaw and do irreparable damage!