Yes, Peter Dixon has great recipes, but you listed pH points in yours and some exotic cultures -so I was wondering where you got them.
I am with Brian too. I think the SR3 is perfect for this. I would consider mixing it with some geo or cheese yeast. I wouldn't use PLA for this one. PLA is too specific aromatically and doesn't really smell like Taleggio. I also think it may be slow to develop at the low temperature in which you are supposed to age the Taleggio.
I would like to comment conceptual about altering formulas.
Protein-to-fat ratio is really important in developing texture and flavor. Generally, cheese recipes are designed to enable the development curve of texture and the development curve of flavor to eventually meet up in sync at some coordinated end point when the cheese matures. The breakdown of fatty acids (lipolisys) creates flavor. Breakdown of proteins (proteolysis) develops texture. If you disrupt the balance between those (oh, say ...by adding cream and tripling the amount of fat), your cheese will render fundamentally different. Cream doesn't make the cheese creamy, it makes it sharper and softer. Creaminess and suppleness are derived from proteins and the lactic bacteria. Easy to remember when planning a cheese:
FAT = FLAVOR PROTEIN = PASTE (or, PÂTÉ)
And so, if you want to get Taleggio, I suggest to stick with the recipe. Use milk without cream. If you are looking for creamier cheese (and in my opinion classic Telaggio is plenty creamy, you don't want to feel like you are eating salted butter), you can play with the cultures to achieve that.
One thing I can't understand; if you have access to raw milk -why would you mix it with supermarket milk? It's like squeezing fresh oranges right into a cup of Sunny Delight!
As far as the formula goes, use 1/8th tsp TA50 per your 1 gallon batch. If it's 100% raw milk and very fresh, you can take it down to 1/16 tsp.