The fuel pressure needs to be the setting that the chip was written in mind with, most(not all) use std pressure, which is 2.7-3.3(vac ON) bar and it will rise to around 3.2/.8 with vac off and plugged.
You need to know from the chip supplier what rail pressure to use in case they use a different one, unlikley as std is way more than enough for stage 3 power.
The above is of no use unless you have a cat/lamda, in which case it is ecu controlled anyway.
Those idle emissions would not do a non cat model any good or go very well at all.
The fuel pressure needs to be set with the vac ON to then just checked with vac off.
You must NOT alter CO @idle by adjusting FP.
CO@ idle wants to be 2.5%CO
tabetha