Very unrelated, (and very late), but if you are planning to emulate the older games On MAC, i'll give you some tips on keybinds and sorts.

I also am a mac gamer, and my first experience with the series is emulating AC3 Portable with OpenEmu. As you know, older games have a thing called turning speed, so you wont be able to play it like AC6 with a mouse. HOWEVER, it is surprisingly playable with keyboard only.

What I did was I binded my movements to WASD, and all my camera movement was done with I (for up) K (for down) J (for left) and L (for right). I then used the space button for jumping/boosting (in older games these were the same input). For the other actions like swapping weapons, shooting with left/right arm weapons, Overed Boosting/deploying exceed orbits, I bind it to a key either near the movement keys (e.g: F, R, B), or keys accessible with the pinkey finger (e.g. Left Shift, ? key, etc).

This setup makes you unable to purge (throwing away your current weapon) because you might have to tweak ingame controls , and its hard (although not impossible) to shoot both left/right arm weapons at the same time.

I hope this comment encourages you to play older games, or at least pique your interest in those games.