Step 1- Measure your chain to the MAXIMUM size you want your bracelet to be, your toggle clasp, plus TWO lobster clasps.
Step 2- Attach one end of your toggle clasp to your chain with a jump ring, as usual. To the second half of your toggle clasp, in this case, the bar, attach one of the lobster clasps. Attach the second lobster clasp to second link from the end of your chain ( this allows it to 'hide' behind the charm dangling off the very last link ;) )
close up of the two lobster connections.
Step 3- Clip your toggle bar onto the chain.
Tada.. you're done.. well... assuming you have your chain full of charms and all pretty looking ;)
You simply move the end of the toggle via the lobster clasp to where ever is needed along the chain for the right fit. The charms will hide the lobster, so all you'll see is the toggle bar ;)
The Lobster clasp on the end can be attached any where along the chain, to hold up the excess when the bracelet has been shortened. This also gives the bracelet a fully look since it doubles the number of charms in that area ;)
Here's a bracelet I made using this technique a while back... you can see how the lobster clasps aren't readily noticeable, especially if you use the same colour metal as some of your charms.
So there you go :) Have fun and please send me a link to any pieces you make using my adjustable toggle idea! Credit is appreciated as well ;)