Combustion question

Approximate readings before and after gas pressure was adjusted. What's better?

Before
Gas pressure 3.6
Stack 295
Co2 6.34
O2 9.2
Co 9ppm

After
Gas pressure 4.25
Stack 325
Co2 7.4
O2 8
Co 10ppm

This is an 80% gas furnace. Isn't it a better burn to try and get the Co2 up closer to 7.5 - 8 as long as the co, stack, etc is at exceptable numbers? I was concerned about the gas pressure being to high, but if all the other readings are good, seems fine to me?

Thoughts, thank you.