The general rule of thumb is to buy a much larger case than you think you need (this is good advice). I would recommend something that is at least 6u 104hp (like the TipTop Mantis). The Pittsburgh Modular cases are really nice too. Plenty of built-in power and connections. I'm a fan of threaded rails too. Sliding nuts are kind of a pain.
Though I don't know what kind of music you are interested in making, or if you already have any external gear to integrate with your proposed rack, you are missing quite a few things that would make this a fun setup. You are definitely going to need VCAs and some sort of sequencing option. You will probably want more modulation options than you currently have. And how will you listen to your results? Do you need a mixer and an I/O module with a headphone output and/or something to convert eurorack levels to line level?
I would recommend taking a long hard look through this forum to see previous recommendations on beginner setups. You will find a lot of questions, answers, and recommendations to make your journey into modular much more productive.
Have fun and good luck!