I have very limited desktop space on my computer table. I have two monitors and both of them are connected to macmini and windows pc in multi-display mode. I don't have space for additional keyboard and mouse for the windows desktop therefore I want to use the mac wireless keyboard and wireless mouse on the windows desktop as well.
You should get a KVM switch (one that supports dual displays, obviously) and connect the receiver for a Logitech keyboard / mouse pair to it.
Inherently, you're only going to drive yourself nuts by forgetting to turn the system you're not using off with using a bluetooth keyboard / mouse and trying to share them between systems (and sending keystrokes where you don't want them going).
Just easier to have a switch designed for this managing it for you (and, no, I haven't priced them in years, so no recommendations...you should do some research)