I'm with Clint, Jim.
On my Akro, I cut the light ply out so the engine sits right on the maple bearers. I then had to cut the inboard doubler out to clear the crankcase.
Put your trippler in and make sure that it covers part of each bearer and runs back to the wing. Fit it to the wing and shape it to a cheek cowl that you like the look of.
Cheers, Geoff