Sincraft, Track IR gives you two options. 1> Have the IR light emit from the unit itself, and the camera will catch what reflects off of the hat clip (included - left of Lusche's pic).
or 2> Purchase a separate "proclip" for your headset that has a cable and produces its own IR light (not included - center of Lusche's pic).
I would guess that it would be quite easy to cut the wire and install batteries, but I haven't heard of anyone doing that.
As for saved head positions... it used to be when you had Track IR turned on, it would divert to the DEFAULT forward view, but it seems that with one of the latest updates they changed that so looking forward with your Track IR shows your SAVED forward view. As for other views, I don't think it matters (if I am wrong please tell me how to adjust these with TIR LOL).
I have two buttons programmed on my throttle... "Center TrackIR, and TrackIR ON/OFF". AFAIK there is no actual joystick setting for this so you'd have to program it as keystrokes through your joystick programming software. There is a third button for "precision mode" but I never bother to turn that on. I find myself turning TrackIR off in tanks, gunning positions, and bombers (doesn't work in F3 mode anyway), so those buttons come in handy.
I also have a bit of 'deadband' programmed so that my view is straight forward for the first 1/2 inch or so of head movement.. this way my aim stays true, especially in planes without reflective gunsights. Track IR is EXTREMELY PROGRAMMABLE! It also used very few resources.
With all that being said, I highly recommend it, and can't imagine how I ever played well without it. ("well" being a relative term, of course)