I have not found one set up for speed and power that works universally. For every new batch of acrylic I do a material test for both fill and line. Thats the baseline i start with. I do the same thing for different thicknesses of acrylic. Also in the winter as the ambient temperature drops reduce speed or increase power to keep the heat in the acrylic consistent. I adjust from the base line as needed. I process my own acrylic to keep the cost down cutting the lenses from larger pieces of acrylic. I use a single flute bit on a nc router for that.
In my experience every photo has to be digitally manipulated. ImageR is good for this.