How heavy should you train and do you warmup?
Always train over your head. Always pick up more weight than you think you can use. Don't ever be sure you can do it. You'll do it. It just depends on how badly you want to do it.
Once you've done it you'll never go back. You get stronger on the first three sets by the way. I don't believe in warming up.
I used to be a dancer and I wondered why some of the girls had big legs. They said they didn't warmup long enough.
You cause VISCOSITY or LUBRICATION off the muscle by warming up and you can't tear tissue down. That's why belly dancers legs stay slimmer. I warmup during the confines of the first three sets!