Just in general, how many could I do so with and how many would I be able to do so and have full installations on a 240gb ssd?
There is unlikely to be any significant upper limit to the amount of menu entries in a grub2 configuration file. Even screen space isn't an issue as you can have sub-menus and scrolling menus.
You are going to be more likely to hit limits with space for OSs before you need to worry about boot menu entries.
Partitioning your drive such that you could fit many operating systems isn't an issue either. You can have three primary partitions with MBR and an extended partition with more than a hundred logical partitions.
With GPT partitioning you can have 128 primary partitions.
Lets you want to use linux operating systems only, reserving 5GB for each one, you could have 48 bootable operating systems. This isn't maximum, it is just an indication of what is achievable.