Need some help with HP Tuners

Posted this in practical reflashing but have yet to get an answer and Im going to be tuning a regular street car this time that got the DOD delete package done as well as an LS9 cam and was told that the other tuner had the LTFT and STFT's at around -15% so he'd like me to do a street tune to get them more where they should be.

if you change the cam, but not the MAF housing etc, do I still have to rescale the MAF and SD errors? Or do I just make changes in the VE tables to get the fuel trims to get closer to 0 than having say, -15 on stft? Which I’m assuming -15 on a fuel trim is that it’s taking out 15% of fuel?

I have made the decision to get very serious serious about learning everything that I can but for some reason I pick up tuning standalones better than these reflashing softwares like HP tuners. So that being said, let me ask you this. Still being new and slowly creeping up with real world tuning experience, how can I learn the softwares so that I know exactly what to do? I was looking in the Holley stand-alone software I will be using in my car and there’s places for offsets and I’m thinking, what in the world is this how do I know what to set these to and how do I use them etc. I want to learn more I need to learn more. Let me know any information.

This is also on an MPVI basics with no wideband hooked up. So can i tell the AFR's through voltage of the widebands that came factory in the 07 truck im going to be doing?

You may find that even with a cam swap the MAF calibration may need some work and if your combined trims are in the range of -15% then yes, you'd want to address this. A -15% trim means that the base calibration is too rich and fuel is being removed. This means the MAF calibration is overestimating air supply and you need to reduce the numbers in the MAF table to achieve this.

Your best bet to see how this is done is to watch the GM LS worked examples in the practical reflash course as we cover the exact process step by step.

Unfortunately to get an AFR Error channel you need a wideband as the stock sensors are narrowband. You don't need the MPVI Pro interface though if you have a supported wideband which can be brought directly into your laptop via serial/USB. That's what i do with our Innovate LM2.