The North American channel for selling Hario,
Roustabout Products shows the
Clear Plastic 6 Cup VD-03T available, but that may be of little help to you in Belgium.
Maybe Hario figures that us Norte Americanos enjoy a supersized cup while the rest of the world is more moderate in their coffee consumption. I donno, I recently scaled back from pouring myself 350 ml to only 200 ml of coffee for my morning commute and once I adjusted I'm fine with it.
For family gatherings, I like the Chemex + Coava Coffee Kone for 1 liter batches. I tried a 1.5 liter batch but bloomed over the side. Stainless Steel french presses also work well for large batches and may travel better then a glass Chemex, but you should be able to use a Kone in a V60. Both these methods give you a lot of body, oil, and some sediment.
Sorry I'm not more help, but I've yet to pick up a Hario V60 cone and lately have been using the Clever Coffee Dripper with 450 ml of water and 28 grams coffee to brew 400 ml batches. Good luck.