Nice builds! One question re this:
I've also siliconed egg crate to the back to give the great stuff background more surface area to hold onto.
How well do you think the silicone adhered to the Pond Shield? I've never used that particular epoxy. The two I have used quite a bit in viv builds (Polygem 307 Lite and Habitat Cast n Coat) both resist adhesion by silicone. Once cured, anyway - it would be worth trying before full cure.
Did you do any destructive testing before full commitment?
Thanks! I'm always looking for a better epoxy!