I didn't read every word of this thread, so if this was mentioned before, please excuse the duplication.
For Glass flower construction
I use hockey pucks for the back of the flowers. They come in different colors. You have to have a way to drill a hole in the side. We have a drill press .... I think that's what it's called .... my husband drills a bunch of them up for me so I have a supply of prepared pucks. Once you drill the hole a rebar fence post fits in snug, so the flowers are held solidly and don't wobble. The fencepost have a V shaped wedge at the bottom that holds solidly into the ground and they cost a little over $1 each.
I use GE II Clear Silicone Window and Door Caulk as the "glue", it is sun/freeze proof so it won't break down when exposed to the elements. I prefer the squeeze tube that doesn't need a caulking gun. The gun is hard for my hands to work with. It's about $4 for just under 3 oz, but a tube goes a long way. I'm a long way from any craft stores, so this is easy for me to pick up. I've had some flower for a few years, and the "glue" has not deteriorated .... I do bring them in during winter. I use this product as the glue for all outside crafts.
I also seen a "plumber's Elbow" used for the back of the flowers.
