I would use the sps plate system with the long dowels to leave room between each layer for the flowers. I love the sps system!!!!!
Yes, use Bakery Craft's Single plate system (SPS) using 5" pillars (sometimes called dowels but they really aren't). This will give you 1" between tiers for the flowers.
If you want more space then you need Wilton's hidden pillars cut to 5".