Hi Dot & welcome. :lol:
The bases that I have seen on the pieces by Max Verboeket, have all been polished and mostly signed. Compared to the vases here for sale in Holland and the ones that I have handled, attributed to Max Verboeket, yours seems on the "chunky" side.
Sorry that I cannot be of more help. :cry:
Ivo is going to be the best person to answer this one, I think.