searching for coarse vermiculite

After calling every nursery within a decent driving radius in search of coarse Vermiculite and having no luck, one manager finally told me the manufacturer of all the vermiculite found locally didn’t make coarse this year. The official book says to get the coarse variety but the man at the nursery I talked to said everyone is using the medium with no noticeable differences. However, on the square foot website it says to start with the coarse variety as it will get smaller and smaller as time goes by. So I am going to keep searching and probably end up ordering it online … even though it may delay my garden