how much work space you need with Logic Pro?

As a rule of thumb, you should have 10-15% free space on your hard drive(s) after installation - no matter which software you are using. If you have not enough space, you risk file corruption and more. Read the technical specification of Logic how much free space you need to install, then do the math.

You might be referring to RAM?

The full Logic Pro Sound Library, including Apple Loops and drum kits, requires about 72 GB of free storage space on a Mac. 

~ThatLogicProGuy