Setting up an HTAP Environment

I've had success in the past with setting up a CIX/PK on an identity column and then setting up supporting NCIX and NCCsIX on tables to help support an HTAP environment. I'm curious, going forward what would be the best combo of Columnstore and RowStore indexes? Should I create a clustered ColumnStore index and then create supporting nonClustered RowStore indexes? Or should I keep with my original design of a CIX/PK on an identity column with supporting NC RowStore & ColumnStore indexes? The main question I have in this scenario is if should I include my CIX/PK column in the NC ColumnStore index(s)? My current position will be supporting a transactional app that will do batch/trickle inserts with few updates/deletes (currently working on them to do zero, but there is a vNext product that I want to get right the first time...) with a heavy emphasis on OLAP Selects. Most tables have a skinny schema with a few INT/Numeric/Float columns and an always ever increasing DateTime field. TIA :) Edit: (Thanks J.D.) Number of rows vary but tend towards the millions with some of our larger customers. Mid range 1-2 million. Large currently 8-9 million. Currently each customer has their own copy of "our" database so it's a nightmare to tune, but we are moving to Azure soonish so we can collect metrics/usage data on each of our customers so math and it's gonna get huge when we migrate over.