"I've decided to use your method, but is there a way to automate that? I'm not interested in using aliases, etc. Every file I see in front of me needs to be the actual physical file. Not some weird link to another location."
Quite frankly, I have no idea what you're talking about -- your post doesn't make sense.
If your boot SSD isn't "big enough" to hold everything, put the essential stuff on it:
- OS
- applications
- basic accounts
You want to keep the boot SSD "lean and clean" with plenty of free space for VM and temp files.
You have a Mac Pro, right? With room for multiple drives inside?
If you have large libraries of things such as movies, music and pictures, put those libraries on another drive.
Most applications that ACCESS these libraries can be set so that they will load the library from any drive that you specify. The process will be automatic and seamless.
Right now, looking at my desktop, I have no less than SEVEN volumes mounted (7 drive icons).
I never have less than that.
I -know where things are-, and where they're supposed to go.