belly tank efficiency trike questions

[ratherbehiking]

Hey everyone, been dreaming for a while about a trike to commute in. found a company that makes fiberglass belly tanks for salt flat racers and had a couple questions.

Their standard tank is make of 3 layers of 2 oz mat and weighs 140 lbs, they can also make me a 2 layer tanks that weighs 105, and I have the option of paying for carbon fiber or fiberglass cloth for an even lighter tank.

I don't know to much about different types of fiberglass, would 2 layers be enough for strength? what is the difference between mat and cloth when it comes to strength?

I would have a tubing frame inside of the tank so the tank itself would not be under much load.