Please educate me on baselayers, mainly for running/walking. I don't want to invest alot of $$$ until I've reached my goal weight. I'm getting back into running. BTW I'm in the midwest(Michigan). I have some polyproplyene tops and bottoms, some tech shirts - Champion C9(from Target)short & long sleeve, 1/2 zipp LS shirt with reflective piping. Could I get by with wearing the 1/2 zip tech shirt as an outer layer? I have a Columbia softshell jacket that isn't very heavy, but don't know if it is something that would be good to run/walk in. Thanks for your thoughts and recommendations.