Well I didn't check this out right away, but I'm not stopped I'm just slow.
My car is still bare inside, nothing in the way.
I got out my defroster thingies. They kind of might maybe fit two of the four outlets in the dash/windshield area of my 55. You would have to forget about the other two if you did it with the parts VA supplies.
Here's the other problem. I don't know exactly what the 56 looks like in this area, but it looks to me like the VA parts are equally insufficient for a 56, though it's different. They are half as wide as they could be for a 56.
I also looked at some articles on installs, as well as VA's own instructions. No mention of the holes you have to drill or any custom fitting, which is needed even if you do the minimum.
I remember my first 55, 40 years ago. The defroster sucked, mostly because the fan was weak. But it kind of worked.
Question is, is the fan on the VA good enough to overcome their built in problem?
Not sure I need "super defrost" - actually where I live you need "super defog", but I wonder how often I get caught up where I need that. I know I need something, maybe what they provide is almost enough.