I use 3's as my starting point for the flowers. I like overlapping and layering too.
I think this page is the basics of clustering. My left corner cluster is 3 flowers and 4 leaves. From there you adjust layers and amounts like the other two clusters. I used to find pages done with the same kits I had bought and then copy clusters element for element to get the feel of what went into other's clusters. Then I'd copy a cluster-y page with a totally different kit to mimic the look with what I had. Anyway, hope this helps.