I've seen some schematics that show caps as having values of 50/50, or 10/16, 6000/50, etc.  What does that mean?  I understand 2200 nF, but not the others.

What types of caps (metal film, poly, electrolytic, etc.) do I typically want to deal with in my amp - does it matter which stage it's being used in?  Is it just whatever I can afford?  If I'm going for a heavy distortion, does it even matter?

I want to buy a bulk assortment to start - is there a recommended place/type to go with or to avoid?

Sometimes the schematics show polarization, sometimes not.  What's the difference, and can I use one in place of the other (so I can just get a bunch of one type)?

thanks.