Brikkas only come in a 2-cup or 4-cup. They’re slightly different than a normal moka pot, in that they have a weighted cap on top of the spout to add a bit of extra pressure. The extra pressure lets it yield a little bit of crema. I realize now that I actually have the 2-cup, so 1 and a half demitasse isn’t all that crazy. It’s actually the perfect amount; I often pour it into a 10 oz mug and top up with a kettle for an Americano.
I have a Bialetti stainless 6-cup, but it doesn’t get a ton of use. The chamber is so large I feel like it burns through coffee too quickly.