Do whatever you want, but be honest with the customer. I can't stand "distillers" who do everything they can to obscure who or where the product is actually made. If you redistill GNS and sell it as vodka, say that's what you do. Say why it makes a better vodka than simply bottling GNS. If you just bottle GNS, say that's what you do, don't call it hand crafted when you buy a tanker truck at a time. Don't have a huge still that isn't hooked up and say you make awesome vodka. You don't make anything, you are simply a bottling plant.
One distiller who makes a good gin said this on using GNS, do you expect a painter to stretch his own canvas to paint on? The GNS is simply the canvas to which I paint using botanicals. I think he has a valid point, but if I make a gin it will be from my own base spirit because that what I want to do