I like heavy armor but wouldn't combo it with a tower shield. I prefer banded when I can get it and then silver shield for style points.

I think root armor is similar to copper as far as rating. IIRC the 1st tier of the next armor is the same (or within just 2) of the maxed out previous armor. So it doesn't pay to say go from max copper to tier 1 iron. Always best to wait till you have enough iron to max 1 armor piece and then another.

I just wear the root helmet in the swamp for the poison resist. Rest is iron as soon as I can start maxing pieces. Iron for me was so short lived and then I had silver. Could try to get silver 1st, but that is a bit dicey in mountains.