Yeah, they were all different sizes.
I got maybe 4 that were around an inch, most of them were between .5 .75 probably, and a few little ones, I put probably thirty into my 10 gallon, and I definitely see them, but they by no means overcrowd the tank since they're so small and spend most of their time in the substrate.
I could probably count 15 easy just poking around the tank, and I figure if I can count half of what I put in there, the other half is probably just eluding me, rather than actually dead.
They did an awesome job cleaning up the brown algae all over my clay pot, and on the white gravel I had in there.
If you have a 10 gallon or bigger, personally I would say the 40 trumpets would probably be fine, my 10 gallon is overstocked for the time being, but they seem to be doing fine.
(10 gallon with gravel, fake plants, one airstone, aqueon 10 HOB filter, one comet goldfish <4 inches, two common goldfish <4 inches, the 30~ snails, and as of yesterday an amano shrimp, and I figure if they shrimp can live in the conditions and -seem- happy and healthy, the snails really aren't affecting the bioload much)