Don't get overwhelmed. Focus first at perfecting the recipes and techniques (otherwise you will never know what you did and what the culture did) - use multi purpose cultures for that like MA4000 series when asked for mesophilic in harder cheeses and maybe MM100 or Flora Danica for softer cheeses. Then use Thermo C or TA culture for cheese that requires thermophilic culture. Once you get it right, start playing with the cultures and see if you like one better than another. They effect the texture and aging time as well as notes on the final cheese such as sharpness, nutiness etc. I didn't use KAZU until I've had about 200 cheeses behind me and believe me, it is nice but it did not change my life of cheesemaking. I still stick with the basic cultures more than anything else. Occasionally I mix a little something in them to make them lean one way or another and augment or deduct some of their character, but not more than that.