Just wondering, since short and long term fuel trims are pretty accurate, can you use the % change in fuel trims as a sensor to adjust overall fueling?

I have never gotten my 02 sensor to work but need to roughly dial something in as I am having lean codes on both banks.

Most of the time the fuel trims are not pinned so I have a real % reading to work with.

Sorry this is a newbie question.

Also my STFT are normally below 10% while long terms can get as high as 24%. Do I ignore LTFT''s and just tune with STFT's?