Hi Alison,
I am a chain mailler, I do some wire work and wire wrapping, and yes the holes in some of the beads require you to use 24 to 26 gauge wire, and yes you should stretch the wire before you use it unless you are going to be manipulating the wire (like coiling it as I do, I stretch as I coil). I guess the long and the short of this is that 26 gauge wire will not hold up to the weight that you are suggesting that you have.
I don't know the design that you have in mind but maybe you should rethink the way that you want to assemble the project to achieve the same affect that you want, not the best news maybe but you are using gold fill wire and you would like make sure that what you make is a product that will hold up to normal wear.
If you post a picture maybe the group can help you with the problem and offer some solutions that won't change the look of your project, but will give you a beautiful end result.
Good luck, I'll check back to see how it is going. :O)