All I can say is I had my Champion done professionally and am glad I did because they cut through the channel that contained all of my wiring going to the bow.
I hope you can find someone there who was around when the boat was built and has some idea of its construction.
Just be REAL certain of where you want it in relationship to your pedestal. I got mine a little closer than ideal but its livable. Seal the cut edges of the deck.
I also plan to silicon the lip of the tray to the deck as well - which begs the question as to whether to run the carpet under the lip or only just up to the edge?