YEAH!!! Pasta filata is a really frustrating family. I think most of us have been there.. trying week after week. Means a lot that you could have a small victory here
Did you use the make I had above? If you did, provolone is about the same, but you really do need some bulgaricus in there for added flavor and for the right texture. You could use a mixed thermo blend or use bulgaricus with the TA. The pH targets are the same... 6.4 before you add rennet, and 5.9 when you fuse the curds and drain. This acidification up front will help to make sure that the curd is ready to spin relatively quickly. And yes, just increase by 3x, maybe a touch less. When you get into larger sizes... 5 gal+, then usually can use less culture.
With provolone, you want to cut the curds a tad smaller to make sure the moisture level is not excessively high at the end.