wet sanding is another way to help reduce the dust from the resin, and it helps to get a nicer finish on the sanded surfaces. I'd still wear a respirator though.
When glueing the PE parts, apply the CA glue to the surface you wish to attach the brass to, not to the brass itself. The reason for this is pretty obvious, if you apply it to the brass, it could stick anywhere, and probably will. at least if the glue is on the spot you want the brass stuck to, that's the only place it can stick. Well that's the theory anyway.