Multiple Primary Machines with a single secondary

So I sent an email about this issue, but I assumed this would probably be a better place to discuss this issue. 

I have used "Mouse without Borders" however with the sheer amount of lag that is displayed in the mouse is very tedious to work with. I've also used Synergy or Symless, whatever they want to be called, but their licensing is a mess. They were FOSS, open source but now they want money, kinda but it depends if you're commercial, or if you want to build the binaries... They probably saw the analytics and wanted to monopolize on it, meh. 

I bought this software through a humble bundle. I didn't even know what it was. I was familiar with the above. After trying multiplicity, it is fantastic. So I want to actually use the software. 

I have a laptop that I'm using for my college course work. This laptop is switching between both my home tower (16 core water cooled behemoth) and my work pc (budget laptop that can't render a triangle, struggles with 2 displays, but somehow used for engineering) both of which I want to have as a primary. I will never use these machines in tandem, I'm either remote, at work, or at home. So the school laptop will always be the secondary as I will transport the laptop between the two. I've tried to setup multiplicity and it works flawlessly until I try to setup the second primary. 

What is the best way to do this or am I limited by some means?