Nice vase!
When I researched my vase I looked at hundreds of pictures of SvdA pieces, and the shape doesn't look like a typical Pinzoni piece with the ultra-thin rim IMHO.
It could still be Seguso though, the colours are allright I think. Just checked, in Judith Miller's "Glas des 20. Jhdts." is a Flavio Poli teardrop shape vase in a very similar colourway.
Funny thing, I saw two vases recently (one at a fleamarket, the other one is sitting in my fav charity shop for ages) which seem to have the identical shape to the ebay vase, but a different colourway (dark brown cased in orange brown). They were quite nice, but not very well made, some irregularities to the surface and bubbles to the glass; so I thought they were probably not Murano but recent Polish or similar production.
But it is such a simple and classic shape, may just be a coincidence...
Other Seguso collectors (kane?) might know if the polished pontil is found on SvdA pieces apart from the usual flat base...
So not much help from my side (as usual

)
Michael