You can't change the A/F with the WB. It only lets you see what the A/F is doing. Your going to need some type of fuel piggy back controller to tune the A/F. Not too sure about the MAF-T but I don't believe it lets you fine tune the fuel curve. Just make some initial settings based upon the type of injectors your running. However the MAFT-PRO does appear to be alot more flexible and allow you to do this. There are several threads that talk to it, do a search and they will pop up.