Very interesting piece. I'd go MS64 on it for the money. Technically, it brushed up pretty good against other coins. But, that isn't the only factor. It looks like it has killer luster. These were special set coins, and that's expected. The dark tarnish tends to mitigate the negative impact due to the technical condition, though, should that make any sense. At least, in my opinion, you shouldn't let this go in the market for under MS64.
Based on the photos I'd say low MS60/61. It may have great luster but there's a lot of chatter in the fields.
Luster looks good, spots on the reverse look bad and the marks on the obverse look worse. I would think MS61/62.
It could very well do that, based on its technical weaknesses. But we're not grading that way, are we? We're overlooking technical weaknesses for eye appeal, aren't we?
Honestly, I'm not certain at all where you are going, so you likely have to help me with this one. The OP asked what we would grade the coin so I gave my opinion and the reasons for the opinion.
You grade coins the same way I do, that's your problem. Lol, Tom. That is to say, I give a ton of weight to the technical condition, too, just as you're doing on this coin. But that doesn't carry the day when market grading. It doesn't carry the day with the TPGs, who are grading, rather, for their markets. I got good eyesight. I see what you're seeing on the coin. I'm saying, for the money, there's no way this coin is going low MS. If it grades that way, e.g., MS61-62, it will be bid at MS64. Technical weakness doesn't carry the day in market grading. Eye appeal carries the day. That's where I'm going. Better?
In all honesty, that coin wouldn't find its way into my collection. Not to put you or your tastes down, but it just doesn't do it for me. I'm collecting classic commems, and, I suspect the BTW/WC will be one of the last ones I add to my collection, just because it's so hard to find nice-looking ones. But, as far as grade, I'm in with the MS62 crowd.