Projects, especially with midi only data take up very little storage space. Once you start to export your tracks to audio and especially to 96khz and above you’ll need a lot more storage and with an extreme amount of tracks and plugins you may notice performance needs will increase also. In your case I would just put them on the 5400rpm drive. Even these drives are in general fast enough to handle tens of audio tracks simultaneously. You can test this yourself by creating a test project and increase the number of audio tracks and see how far it will go?