Epoxy Resin Pyramind Question?

So I am creating a pyramid mold using epoxy resin as a gift, and because it is a special gift I wanted to incorporate dried flowers that I have collected over the years from meaningful places/events. Unfortunately, I am having problems because my color scheme is dark colors if I let them float in the resin you won't be able to see them much also that wasn't the idea/look I was going for. I want the flowers to be pressed up against the sides of the pyramid so you would be able to see them and their color better.

I did my first, tester of a small portion of what would be the large pyramid in whole, everything looks great, but the flowers are what I struggled with. I first put in the flowers and pressed them against the sides of the mold, poured in the resin, and used my heat gun for the bubbles. But that caused only some of the flowers to be visible like how I wanted, some you can't see at all, and some are partially pressed on the sides but started to lift off as it cured.

What do I do? Should I glue the flowers to the sides before pouring in the resin? (and if so what glue) Should I Pour in the resin first, then use the heat gun and then insert the flowers? Should I apply a thin coat on the sides as a kind of glue and stick the flowers on and then, later on, fill the space with resin? I do not want to change my color scheme because it's for a male.

I have attached a picture of my tester.