I have never heard anything by Watanabe.
And yes, it’s a bummer when a reel to reel tape turns out to be a 3-3/4. If I’m not mistaken, I have, or had, a couple of Szell/Epic ones like that.
Edit: Wrong. The couple I have are 7-1/2. It’s either something else, or the offending articles left the building long ago. So never mind. Move along, nothing to see here.