So something almost like tassel?
OK, here’s what I’m thinking. When you have exposed thread between the rhinestones, that is an invitation for the strands to get tangled. That tendency would be less noticeable in a cluster, which is good.
But the bad thing is that, as the individual strands tangle and move against once another, the glued rhinestones aren’t going to fair well.
I think what you want to experiment with is rose or chaton montées. Here’s an example. They can be strung, rather than glued. What might be really cool would be to string red bugle beads between the montées. They’d add sparkle but would blend in with the dress fabric. And they’d help keep the strands from tangling.
The difference between the rose and the chaton, BTW, is that chatons come to a point in the back but roses are flat (not as flat as a flatback crystal, though). The chatons have a deeper mounting cup. I personally think roses would work better.
For bead weaving and bead embroidery, I use 6 lb. Fireline, which is a kind of fishing line. It’s not monofillament. (I buy mine at WalMart in the sporting goods department.) So here’s how I think I’d approach this.
I’d start with a small piece of felt or Ultrasuede that matches the dress color. The cluster is going to be anchored to that. Knot your thread and put your needle through the felt/Ultrasuede (hereafter referred to as the “base.”) String on any combo of montées and bugle beads to the length you want. At the end, you’re going to want some sort of anchor bead. If you want the bead to be another design element, you could use some kind of drop bead. Or you could keep it subtle and use a seed bead. Stitch through the anchor bead and then take your needle back up through all the bugle beads and montées. Stitch through the base to the back side, then stitch up through the front again and repeat the fringe process, as many times are you want.
When you’re done, attach the clusters to the dress by stitching the base to the dress fabric.
This sounds WAY more complicated than it is. If you think it will work, I’ll find you a diagram that illustrates the basic technique.