I have just been through this with TS3.5 MAX
1. The CS and SE items are redundant you don't need them unless you want to only have those on a system with low disk space.
2. Be aware that your download rights expire so just download and install EVERYTHING other than the CS and SE.
3. Before downloading plug a USB drive in and redirect the IK Multimedia downloads to that drive. I redirected mine to J:\IK and everything is in there. In two years if you want to reinstall and your download privileges have expired you can reinstall from J:\IK files. Also as a bonus you won't run out of drive space on C:\ because to download 200 gb of STUFF and install it you would need almost 500 gb free space on C:\.
4. If even after using an external download folder you can't fit everything you can even redirect (at least on a desktop pc with more than one hard drive) all the IK Library content to a second internal (fast!) disk drive without much trouble.
5. If you want some space back uninstall later whatever you tried and didnt like. But do it all before your downloads expire.