+1 on not being a pussy and going for it even though it's new to you. my trunk pan is a little rotten, and a lil more rust near the rear left quarter panel. car is from the south
. i too will be picking up a mig soon and giving this a shot myself as i've never done any body work myself. if i were you tho, i would trash that rear subframe and those springs/struts/ca's. pickup some suspension parts in better condition, OR fucking clean all the rust off and undercoat it or powdercoat.
as mentioned before, i would take a
little more time with grinding those welds down and neatly applying/sanding that bondo down to a smoother, more uniform finish.