ok, so right now on my acoustic i've been using some kind of strings from hell--some kind of zinc or copper POS. they don't keep tune, and sometimes i'll get string sag and sometimes not, its really messed up. anyways, so i'm gonna switch back to normal type strings, but i dunno what type to get. nylon, or steel? i like to do a lot of City and Colour and The Spill Canvas, but I like the feel of the nylons? help, plz.