Space Case 4pc grinders... How much will fit?

Giving it another try with my post without breaking one of the most obvious forum rules this time.....:)
I´m considering buying a Space Case 4pc grinder/sifter but I´m unsure what size is best. So I wanted to check and see if anyone has one or knows how much herb the different sizes has room for? A bird whistled in my ear saying the small size has room for around 1 gram. But how about the medium or large size?
Size measurements are...
MEDIUM: 2 1/2"" WIDE x 2"" TALL
LARGE: 3 1/2"" WIDE x 2 5/8"" TALL"

Thanks alot!