Hey Matt, it's an old post - me too looking for Land Gear offsets. The ones in the PMDG SDK don't seem to work. Have trawled the net but only found 1 decent reference but using sim-connect which I don't use. Did you ever get it working?
As for the 12V out, that is just a nice thing FDS put in to be able to daisy chain to another syscard and essentially will use the same power supply. If you only have one card then you don't need to use it.
But going on the post you probably know all this by now...
