The SC1000 system should work just fine on your EFI. Here's a link to a page at Mercury that will tell you a little more. I have the SC1000 System Tack/Speedo, but I wouldn't know how to install it (and what to un-install) to save my life. My dealer says they've never installed anything more than one of the system monitors, so they have not been much help, either. At this point, I'm hunting around for another dealer with more SC experience.
How about some more photos of your neck of the woods. The only part of Africa I've seen was hot sandy and the people lived in tents with their donkeys.