Help on Fiberglass Mold Making....for Silicone project

Hello, I am making a full body silicone mermaid tail. I'm wondering what the best way to capture the detail in my clay sculpture would be (I am using Monster Clay)

This is my first time making a mold of this size and after some research it seems that using Bondo all purpose fiberglass resin would work.
I also read that using plaster strips first and then Bondo on top might be better for detail. I am afraid of using plaster as I know that it can crack easily.
Also, what would you recommend for a release agent?

Can anyone clear this up for me and give some insight? Any tips are much appreciated! ~Tess

For capturing all the detail when molding with fiberglass, I like to do a mix of bondo and fiberglass resin for my detail coats. In my experience using just fiberglass resin is too runny, and it's hard to get any sort of build up with it. I usually do two coats of a milk shake consistency, followed by two thicker layers. I then back that up with 3 to 4 layers of fiberglass. Good looking sculpt by the way.

You might want to coat it first with gel cote- it's a more "plastic" coating than the fiberglas, and easier to sand. Fiberglas molds I've made had an inner layer of gel cote, followed by fiberglas cloth and resin backing it up.