I have some interesting things I want to try in the future, but this will be my first IC design and people are still generating open source IP for the PDK, so I want to keep things pretty simple at first.

I think you're right in building up slowly but you've piqued my interest - what you thinking of doing in the future?

Its going to depend a lot on what can get included in the free shuttle runs and the pricing of any multi project wafers, but I was considering trying to do some stuff with resonant switched capacitor converters

Nice, a very interesting topic. I've done some feasibility study work on both resonant converters with on die transformers and switched cap charge pumps. Resonant switched cap converters is a lovely combination of both those concepts. I look forward to seeing the work once you get started.