If you are using swarovski crystals, you need to use something heavy duty. I took a class in RAW (right angle weave) to make a tennis bracelet, and I love the results. We used fireline for that.
I am told the more strands of wire, the stronger it is. I use, I think 49 strand for wire.
I haven't tried the mag clasps yet, but I do have some.
I joined a kit of the month club, for about 10 bucks a month a complete kit comes in the mail. I have gotten two, the first was a 4 strand necklace with a two strand bracelet, the second is a bracelet made with memory wire. Loads of fun.
This all started for me because I wanted to figure out how to fix the necklace I got from Chrystal Paths a few years back, and my pearl necklace. Haven't done that yet, but the other projects have been fun. So far a beaded lanyard for my work id, and eyeglass chain for family.