Assassin Snails

Does any of the gang have experience with Assassin snails being mixed with other ornamental snails...?  Also, what are the chances of just getting one Assassin snail and keeping at just one...?

Reason for asking:  I have significant numbers of tiny little Ramshorn pest snails, which never grow to more that about 3mm diameter, but I also have Nerites, Faunus & Rabbit snails...    In an ideal world, I would love to have a single Assassin snail that merrily went around controlling the tiny little pest snails but left that larger ornamental snails alone...  Probably asking a bit too much here, but fingers crossed somebody may have had a similar problem down the line...

Thanks Matt... 

The numbers of the little Ramshorns do seem to be in slow decline, especially since reducing the protein based fish foods and just looking at feeding regimes as a whole etc...  Could be that I just need to listen to my own advice in regards to time and having patience etc..?  There could be a risk of even one solitary Assassin snail potentially running out of the little ramshorn pest snails and turning to the other ornamental snails out of need - perhaps I should aim to control the pest snails more naturally first...?

Thanks Donna... 

I think you're right and probably wiser to let time take care of things...  The Rabbit snails are reproducing, albeit very slowly, so this means there are a small number of baby Rabbit snails in the tank which would probably make an ideal target for an Assassin snail...