Just a comment on which computer should be the primary computer:
I also have two computers, a desktop and a laptop.
My primary computer is my laptop as it can go anywhere I go. If I go to the library for ancestor research the laptop goes with me. If I go to the cemetery for research the laptop can go also. If I go to interview an older ancestor the laptop is there.
With the best laid research plans, there is always something you want to check. Maybe you will find a surname in the cemetery you were not expecting, you can easily check the laptop.
You want to clarify a family with the person you are interviewing, open the laptop, show them the tree, and correct it they point out flaws. If you want to check the information enter the person's comments into the notes.
I have an home LAN. While FTM is not on the desktop, all of the FTM files are backed up to the desktop through the LAN, so I have duplicates of my data on the desktop. I then back up the desktop to and external disk.