I use TA-61 and LH-100 for my thermo cultures. TA-61 is S. thermophilus. LH-100 is L. helveticus and L. lactis.
The S. thermophilus bacteria in TA-61 is a rapid acid producer, but does not do a good job of completing lactose breakdown. So you generally do not want to use TA-61 by itself. That's what the TA-100 is for, but the ratio is very important.
When making regular Swiss types, I use a 50/50 mix of TA-61 & LH-100, plus Propionic of course. This blend will take longer to break down the lactose and the bacteria will be active longer.
When making Italian types like Parmesan or Romano, I use a blend of 20/80 - 20% TA-61 and 80% LH-100. Because there is less TA-61, the cheese does not acidify as quickly. And because there is much more LH-100, lactose will be broken down much quicker. This allows enzymes, like Lipase, and proteolysis to kick in sooner. Good Italian types depend on a lot of enzymatic activity over the course of several months or more to develop really sharp flavors.
You can buy premixed blends of TA-61 & LH-100, but those "store bought" blends ignore the ratios. I prefer to custom mix my own.
When making Baby Swiss, I agree with Dixon on the Meso cultures. I use a blend called Meso Aromatic B to get diacetyl flavor and additional CO2.
I keep 2 kinds of Lipase - Regular (mild) and Italian. I use the sharp Italian version in all of my hard Italian cheeses like Parmesan or Romano. I use the mild in Mozzarella & Provolone.