I would NOT place anything under the glass again, except for paper graphics. I had a real problem preventing air bubbles from being trapped under the glass and I never did get it to look as good as it could have looked. The maple leaves also let go in spots creating an opaque area through which nothing could be seen except a dull off-white spot. I strongly suggest you embed your objects on top of the glass, ideally before doing any fill coats to minimize the bulge you will get from the objects. I am working on embedding metal flake right now and I know that the maple leaf graphic I am filling out will be a tweak higher than the rest of the deck, no big deal. I can always smooth off the edges of my work to make it appear flat but that would require more work than I am willing to do and add weight, use more epoxy ($$$) and slow progress. I think if you were to embed your butterflies and flowers in epoxy first, pressing them flat while the epoxy cures, then set them onto your deck, you will have a far better end product. I am about to post images of the work I did today, stay tuned, they should be posted in a few minutes.

Robert N Pruden