If you have other snails, I'd advise avoiding MTS. They breed too fast and basically consume most of the available food before other snails get a chance.
I had a Golden Mystery Snail hatch 100+ eggs. Once they were the size of a BB I started to move them around to various tanks. While some fairly quickly got to the size of a nickle, none in the tank with the MTS snails was got larger than a pea. I eventually moved them out because they were hardly growing and were dying off.
Once your MTS population reaches a certain size, it stops increasing due to lack of food. I also found that once this happens the MTS start growing very slowly. The only really big MTS I have is the original I found as a baby and decided to keep (it's the mom/dad of all my MTS). Also, once I removed a large number of MTS and noticed the remaining MTS increasing in size rather quickly.
I'm glad I saved that one MTS, because now I can have fun breeding assassin snails! I've had them for a few weeks. Lots of empty MTS shells now, and a few assassin eggs.