Lovely vase.
I saw it when it was for sale, was very tempted (as the prize was nice, too), and did quite a bit of research.
My conclusion was different, though...
To me it doesn't look right for a Ermanno Toso vase, comparing it to the pieces found online and to the pictures in the Fratelli Toso book.
First, the whole thing looks a bit too massive.
Second, the pinwheel murrine in Ermanno Toso vases never seem to have 14 arms like the ones in this piece. I compared it to dozens.
And third, most important, the construction looks totally different to me: while in the "real" pieces the pinwheel murrine are placed next to the yellow murrine, in this vase they seem to be layed on top of the yellow murrine layer.
I certainly do not know if these differences are enough to discount Fratelli Toso as the maker, but I decided that they were to me. I may be wrong

Michael