Best Source For Dried Porcini Mushrooms
I am very happy with a 1lb bag of "Super A" porcinis that I ordered from JR Mushrooms & Specialties. I find that the size of the mushrooms actually varies, with many of them being quite large (up to 3-4"), but the bag also contains various smaller pieces, too, which I suppose happens simply with shipping and the nature of the dried product.
On opening the bag, I very roughly sorted the largest pieces into one ziplock bag, and then put the smaller ones into another bag. That way I can go for larger ones when I want them (usually pizzas) and the smaller ones when they are better (risottos, cacciatore).