Tuning is more complex than that.
For custom tuning, You have to use a wideband or your guessing at the targeted corrections.
In a stock configuration, your already getting about 6 degrees of knock at WOT and 3 in some areas of part throttle.
From the factory, GM loads it up on fuel for a rich mixture and because of that in some areas it can tolerate more main spark. You may end up reducing spark in some areas of WOT instead of adding, but having a better AFR and no knock to make more power.
For my custom tune im plugged into the car with a wideband, and I reconfigure the mapping to default the vehicle to run in open loop and closed loop during my tuning process. My tuning process takes about 3-4 hours.
I run the car at in a steady state at 1500, 2000, 2500, 3000, 3500, 4000 RPMS, and then let the RPMs drop naturally to 1500 RPMs. I’ll make changes and do it again and again and again until im happy with the fueling on the trims and spark for cruising. For the vehicles with virtual VE tables, the process is slightly differant, or you can rescale the range where the VE table is used and dial in the MAF more and or use additional software to scale them.
Ill neutralize the LTFT for WOT so they don’t interfere with my target AFR, and make my WOT runs to optimism my targeted fuel range with spark. After im happy with that, I turn on the LTFTs for fine tuning to see how the vehicle is running at operating tempertures.
I do many more enhancements to the mapping, but you get the basic concepts. If you do a google search on how to tune an LS motor or LS tuning guides, there's a ton of information on the web. Most of it written by guys on the HP Tuners forum.
Save your original tune to a couple of thumb drives so you'll always have it, and go slow.
www.TampaTuning.com
Phil