@PaulWhite Thanks, that's a great answer and touched on a number of things I didn't know about. Yes, I'm reconsidering the 15k partitions. I don't need nearly that many for how I'm currently using that table.
@JamesLupolt Oh one thing I forgot to mention. It's not important to the answer, but to avoid running out of memory when creating the clustered and clustered column store indexes in the setup script, it helps a LOT to create the heap as partitioned up front.
The compile time for e.g. the single row inserts is just embarrassing.
Well I'm headed off for a while. Thanks again for your answer @PaulWhite. It covers the intersection of a few different topics in some ways I hadn't know about before.