Yamaha Command Link Square Installation Manual

I picked up a used 2012 Yamaha F250XCA 4.2L four stroke for my Parker and and am in the process of installing the new DEC command link controls. I expect to have everything wired up next weekend (I hope) and have a couple of questions for those of you who may have had some experience replacing the old manual controls/gauges with the DEC command link controls/gauges.
My control kit came with the 6YC multi-function gauge. This is the square gauge that takes place of all of the old, separate tach, speed, fuel management gauges. I have a question about how to calibrate the unit to know what my fuel tank capacity is. The instructions show an option for a single point calibration as well as a multi-point calibration. In both instances, the instructions say to run your fuel tank dry, then program the unit to perform the calibration of choice. Then fill your tank and you are good to go. I have about 120 gallons of gas in my tank and have no intention of draining this for the purpose of calibrating a fuel gauge. Can I choose the single point calibration, then program the unit to reflect the 155 gallon capacity of my tank when full-----then fill my tank? This is sort of how I used to initially set up my old flowscan units on older boats. I never ran the tank dry to perform the initial set-up.
If I can do this as described above, then starting with a full tank of fuel, I should be able to then run about 50 or a 100 gallons of fuel out and refill the tank. Then compare the actual amount of gas it took to fill the tank to how much the gauge said I burned. Does anybody know if I can do this with the 6YC command link gauge?
Also....not related to the fuel question posed up above. Once I get all of my new command link stuff wired and plumbed to my new (used) motor, someone has told me that I then have to have Yamaha program my new command link gauge to 'talk' to my engine before it will even turn over. Ugh. Does anybody know about this process? Is this something that has to be done? Can I do it myself? Is the software and computer to engine harness available?
I am too used to the old, non DEC engines. Any help would be GREATLY appreciated.