We have 12 huge, intricate brackets to replicate. Laying on the hypotenuse they are about 2 feet tall and 4 feet wide, with 10+ ivy branches/buds/something inside them. Thus I plan on gluing together sheets of plywood to get 1.75" thick and using a CNC machine to mill them. In the wasted space on the 2'x4' plywood pieces I plan on milling pieces to build some 4"+/- thick corbels and other details.
But is plywood a terrible idea? I was recommended marine grade plywood, but that adds $1000 to the cost and apparently the only difference is there won't be any voids, but I don't mind using a little wood putty to save $1,000. I'm worried they will feather or delaminate in the weather, but if I paint every surface will that preserve them? They won't be directly in the rain but weather often moves sideways around Boston.
The picture shows most of the pieces we need to make. There are also some 12" tall or so pieces under the eaves.