Fine tuning speedometer 8L90 2017 sierra 5.3

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I have adjusted the Speedo using the gear and tire wizard. But now the Speedo calibration is way off vs gps?.
Stock tire size was 265/65r18 657 revs per mile
new tire size is. 275/65r18 663 revs per mile

For instance 90dash is 82mph gps. Do I remove vss revs or add in speedo calibration? And what is a good starting point. 5 or 10?

Did I miss something?

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Factory read program indicates a 31.25? tire 2494mm, ratio 3.42
vss dist ecm 9056=645.40mi
Vss dist trans tcm 5006 = 401.03mi

New settings using gear and tire wizard 32.1?
2561mm, 3.42 ratio
Vss dist ecm 9056=628.30mi
Vss dist trans tcm 5006=390.41mi

These setting shift better but Speedo is off a lot! Please help me with understanding how to adjust this Speedo