Just sent for an ECM programmer/tuner:
The one I ordered was a JET Performance Dynamic Spectrum Tuner Programmer
Beforehand, I watched this video about tuning for fuel economy, though the guy did some (to me) questionable and/or unexplained choices. Also he completely omitted test results, which was highly irritating. Nevertheless I thought the video was interesting stuff.
The Hp Tuners programmer he used does not work with '96 K1500 trucks, but the above mentioned JET programmer does so that's why I ordered it. The user interface is a lot more primitive, but I think it will program whatever is available on a '96.
My main first interest in programming will be transmission shifting points, since so much of my driving relates to hilly twisty roads in the 35 to 45 mph speed limit range.
I'm not going to jump into engine mixture games at this point.