multi strand math help!

[fromvenuswithlove]

Hi guys,
I'm planning on making that necklace from the opening scene in breakfast a tiffany's, the six strands of pearls with the diamond centre piece (only i'm going for four stands of plastic 12mm pearl beads and using a vintage brooch). 
The bit im battling with is how long to make each strand, as they get longer further out.  How do i work it out, I know trial and error could be a goer but i'm a little pressed for time.  Help! 


for reference:

[ScotSkipper402]

Would it help to count the visible beads on each row? Then string the shortest strand to fit your neck, and use the proportions from the original strand counts.

Well, it's clear in my head

[ScotSkipper402]

PLUS, I'd assume that the back beads are approximately equal to the front beads.

[AmberLu84]

Okay, this might help, but it might not.  Recently I restrung a triple stranded pearl necklace for my boyfriends mother. It was her great great grandmothers. (talk about being nervous to work on something!) Anyways, what I did was I took a towel and put it on a flat surface. (The beads on this were of varying sizes, if yours are one size it'll be MUCH easier.) I made sure to measure the very top row of beads so then I knew about how long the necklace was where it rested at the base of the neck. Your starting with a blank canvas so you can actually just make the first row as long as you want, provided it'll fit. I then laid out the beads in three straight row lines in front of me and add an according number of beads to either end of the second and third row to make them longer then the first. I'll put dots (O's) below to see if it can explain any better then me jabbering. That's the easy part. The kicker is when you go to string them, if your not stringing them all together as one it's a bit simpler, but you'll want to make sure to keep your strings really close or they can slip and it makes your necklace sag in some spots. I will see if I can get a picture of the necklace I did so that it might help.

Dot Diagram:

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I really hope it helps. Feel free to PM me if you need anything else or if I haven't explain well enough. Good luck!

Happy Beading