Yes... you do need a Wide band air fuel meter to get the most from your machine as far as tuning is concerned.
Also the lower flow injectors helps with lean rich adjustment capability.
That is if your machine is on the rich side less controller.
Or you could buy the updated tuner.
As far as the lights go....
Green only is for idle up to full throttle.
It is a base setting the other lights (yellow & Red) adjust to.
Yellow only is how much extra or less is added during acceleration.
Red only is for how much is added or reduced for full throttle.
Green with blue flashing is for how soon the extra fuel starts to be added from the start(idle).
press - it starts sooner, press + it starts later.
Yellow as well as Red with blue flashing is the same as green.
- sooner / + later.
For example. If you have a 12.5 idle & it goes to 10.1 when you accelerate it could be one if not both of two things.
Yellow is coming on too soon(yellow blue setting) in relation to the CPU's original enrichment settings or yellow is too rich (yellow only higher #)when it is added.
But... if it goes rich initially & then leans out before full throttle.
I would make the yellow come on later & richen up the yellow only # setting.
That's my story & I'm stick'n to it.