Hi. Your use case would be best served as a single-bin data-in-memory cache, or single-bin with data on SSD. Please read the knowledge-base article on the topic when you make that decision.
Depending on the namespace configuration you decide on, you’ll want to do capacity planning to figure out the size of the nodes and how many of them you need in your cluster. There’s also an article specific to Amazon EC2 capacity planning. If you run into problems you can ask the community for help in the Planning section of the discussion forum.
As long as the data is related, I would keep it all in a single set.