Building 1 time use mold. input?

[Dave Hirshberg]

I've been commissioned to build a Livewell for sportfish. It will measure roughly 40" wide by 24" high by 16"deep. And it will be visible on three sides and the top, backing up to the transom on the cockpit of the boat. I plan on building a one time use 3 sided custom mold for the job. First I plan to make a template out of wood for the top and bottom roughly in the shape of a capitol D if you were looking from the top down. I then plan to lay-up a rectangle of 1 1/2 ounce mat and resin over gelcoat on a flat waxed melamine board and form it(gelcoat side in) around the top and bottom plywood boards while the fiberglass is still relatively green or before it completely hardens, using screws thru the thin fiberglass laminate into the plywood to hold the shape. I then plan to beef up the outside of the form and lastly lay-up my three sided part in it. I'll add the bottom and back of the well afterwards. the only thing to come from the mold will be a shell with a front two sides and a top. I'm good with glass and paint but I'm wondering if there isn't another material out there that lends itself better to bending a tight radius like the two rounded front corners without breaking. I'm sorry if this looks like Greek to you all, I just know some of you have used some West Products and epoxys which i have no experience with. Any Suggestions are appreciated