Advice on small piece castings

Hi, I’m having some issues with a small clear piece that I’m casting and need some advise.

I have a two part mold so I can cast a clear windshield of a toy car 1:64, which is one piece with all five sides  front, rear, sides and top. Some parts of the piece the material is very thin close to 1/16 of an inch thick.

The issues are the following:
1. I’ve used an epoxy resin, but its not rigid enough. I’m looking for something durable and hard.

2. The material needs to be more like in a thin liquid form, as in some areas the material did not fill in the mold.

3. I’ve casted a clear piece and the clarity its ok. But the piece needs to have a transparent dye in the material.

I do really appreciate anyone with suggestions.

Thanks!