Yeah, I don't like those plastic trays either. It's so easy to glue in a couple of hardwood rails to screw the servos to. Any good hardware store will have a selection of square hardwood sticks to build these trays from. As campgems said, you have to build something to screw the plastic trays to. You might as well just build it so the servos screw directly to it. I keep a selection of square and round hardwood sticks on hand at all times, roughly from 3/16 to 7/16 or even 1/2 inch.