Attaching flowers to an arch?

Hi all! I’m wanting to attach flowers and greenery to an arch that we’ll be renting from or venue. They’ll be real flowers and greenery, and from the internet I’ve identified that I’ll need to use floral foam cages and I’ll attach the cages with zip ties to the arch. If you’ve done this before, I’d love to know details and see your photos, or just hear any advice you have! Here’s some of my questions:
-What size floral foam cages did you use? I think the Oasis Grande size will work, but there’s a larger Jumbo size option. (If you have pictures of the finished thing to compare, that would be amazing.)
-Does it work to bring the cages pre-loaded with flowers to the venue and just attach them there, or do you need to attach the cages without flowers first?
I’ll attach some photos as well - this is kind of what I’m thinking of but without the draping.
Thank you!