255/45 x 18 seems the popular size. It’s what VW fit to the Sportline vans. I’ve used the Goodyear Winters and currently have Michelin Cross Climates, there’s other options if you don’t need the load rating for a T32.
Both stood up well - the Goodyears are definitely more of a Winter only tyre, but I’ve had the Cross Climates on all year and wouldn’t say that there‘s a big difference in the Summer months, let’s see how they get on over the Winter as well.
Both are good from a noise perspective, which is a bit factor for me.