A/F/R gauge for tuning

the basic one of these has served me well enough
https://www.aemelectronics.com/prod...ego-afr-gauge/digital-wideband-uego-afr-gauge

and if you can put it in eye line when doing the work
and pop it under the dash visible but not in yer face when work is complete

less change of hitting something :)

use your phone to record a commentary 2500 13.5 2600 13.8 etc etc