Your board cracked at the edge in the top picture? I think you swapped the terms, coilers and doneks are extruded but you want a sinistered base for this stuff. How I understand it, an extruded base is solid plastic. A sinistered base has tons of little air pockets in it, it's very porous, which is good for wax absorption but in this case very good for resisting tempature change. Vinyl windows kinda work the same way, the frames aren't solid plasltic, they have air chambers, the more, the more energy efficient they are which is to say they resist the changing the temp between inside and outside.
I'd like to give this stuff another shot sometime.
All you can eat taco bar tonight at the new restaurant I think.