You did not say which model MFD you have on your boat. I am also a Mac user and the quick and easy solution if you have a TZT 2 or TZT 3 is to use the Time Zero cloud service on your laptop or even better, use the TZ iBoat app if you have an iPhone or iPad. Create the waypoints on the computer or iPad and then just synch the plotter to transfer them.
This assumes you have internet access at your boat through a wifi access point or by using your phone as a personal hotpot. It is necessary to connect the TZT 2 or TZT 3 to wifi and log it in to your TZ Cloud account for it to synchronize the waypoints and routes you add via the app or web cloud interface.
I do this all the time when fishing offshore. I look at the sea temperature charts at home and create marks at promising spots. When I turn on my TZT 3 displays at the boat, they automatically connect to wifi and synchronize so I am ready to go without manually transferring the new waypoints.