Since your CYA is high and the only practical way to lower it is to do a partial drain/refill of the water, I would just do that to start with. Unless your fill water is high in TA or CH, then this partial drain/refill will lower those parameters as well (you can test your fill water to see, or look at your water district's water quality report).
To know how much to drain/refill, you need to know the precise CYA number -- not just that it's "high" since that could mean anything. If the pool store doesn't do accurate tests or won't give you specific numbers, then you should get yourself your own test kit and do the tests yourself. In fact, you should probably do that anyway. It's not hard and you'll take charge of your pool. You can get a Taylor K-2006 from Taylor here
or from poolcenter(dot)com here
or from Leslie's here
or the even better TF100 test kit from tftestkits(dot)com here
The green went away when you lowered the pH since you did that to do the lowering TA procedure which is described in this post
. However, since you probably have to do a partial drain/refill to lower the CYA anyway, I would do that first and then see where the TA level is at.
As for the metals in the water, you can deal with them in one of two ways. When you have the pH low for the TA lowering procedure (after you lower the CYA level first through partial drain/refill), then you can add a metal sequestrant which will keep the copper in solution. The other alternative is to raise the pH, say by shocking with lots of a hypochlorite source of chlorine (unscented bleach or chlorinating liquid, or if your CH is low then Cal-Hypo) and when the pool turns greenish, use OMNI Liquid Floc Plus to consolidate the particles and vacuum to waste. The latter method, however, has the risk of staining the pool surfaces when the pH is raised and before the floc gets used.
Of course, a partial drain/refill will also dilute the metals (copper) in the pool as well, unless your fill water is high in metals (probably not, unless it's certain kinds of well water, but usually well water is just high in TA and/or CH).