Where do you get your substitute for Dollar Tree Foam Board?

[RICHARD PHP]

How do you like working with it? About the same weight per sheet?

At the moment I have only made a swappable power pod for my plan built Storch (made from crap amazon foam) but as soon as I finish my FT storch kit I am going to make an Edge 540 from plan, I also have a 540 Edge kit in the post somewhere........ I will be posting some pics when I start this.
The power pod is a lot stiffer made from 6mm