September 3rd, 2014, 17:15
Greetings, Kodiak! Welcome to a world of continually expanding possibilities! CFS3 is capable of enormous modification, a lot of it in easily edited xml-based files. So it sounds like you are already well-equipped to do the necessary things, from past experience.
To do justice to CFS3 you will need to be methodical and not try to do too many things at once. Take lots of notes if you need a prompt later on. I embed a simple txt file in each of my installs, to remind me of the state of play (eg. modded to 3.1a standard). So to answer your questions my first recommendatoin is to create a clean install patched to 3.1a. This will enable CFS3 to handle multi-engined aircraft.
All your subsequent stand-alone installs will then be to 3.1a standard.
Next question is Firepower. ...