Hi Jerry - Good your experienced with the epoxy. I chose 1/8" as this doubled the stiffness of the beam with the calculated stiffness. I wouldn't go thicker, prefer to make the timber bigger and stay with 1/8". But if you use 2x LVL I suppose 1/4" gets you more stiffness.

Some of the laminated ply with aluminium: the Al is a very soft grade which won't take bolt loads very well.

Here's some scrap for you? Peter