So I don't think anyone will get Spare Refrigerator unless it can be gotten at the final Wily Stage (which, the achievement does NOT clear on whether or not it can).

The amount of practice required is far too great to be going back through Freeze Man's stage ever 3 times you fail at it. The Junk Shield also helps VERY LITTLE, and is mostly only good for finishing him off quickly if he's close to done anyway (does more damage than a charged buster shot). And I can say that while I have gotten better at fighting him, I am done wasting my time on it. I suspect everyone else will have trouble with it as well.