switch machine installation question.

I have glued 1" styrofoam to 1/2" plywood on my n-scale layout and am now fitting the track and roadbed.(perhaps I was too hasty gluing the foam down?) I would like to install atlas under table switch machines, but the thickness of the plywood, subroadbed, and roadbed exceeds the 1" stated in the instructions.

What do I do from here?

Cut a trench in the foam, install the machine and patch it up?

Or will the tortoise machine be a better fit. I have not had a look at one yet.

Any suggestions greatly appreciated as always.
Thanks for your time.

Tony

Tortise, may need to substitue a longer actuation wire