Very good
re: LCD watch how you hook up the power, make sure you are connected to battery power, not ignition, also be very deliberate when connecting it as it can get amnesia if the initial power hookup (or ignition switch bouncing) is too jittery. Auto turn off is in the works, I just have to decide on a solution I like. Use the middle button to turn off the LED backlight for now if you are worried about the drain.
re: vss, I've seen it listed as 4102 pulses per mile, but I think we are counting the rising edge and falling edge of the pulse I think so you need to try 8204. (more = slower)
re: injector, higher microsecondsPerGallon means better displayed fuel efficiency. Once you get the speed/distance dialed in take a look at your mpg readings and modify microsecondsPerGallon by the percentage you think it is off for an initial setup. Eventually (we are still bleeding edge here remember) we will get to a point where you can run a whole tank through and see how close your guess is.
re: vin vs ground, put your ohm meter leads on them and see if there is 0 ohms between them. If so then they be the same.