The process of "Discovery" is truly awesome, IMO. I'm glad you feel the same
So without looking at what your Lambda1 corrections or what your Lambda 2 readings are with the WB 02 hooked up, it's hard to say why it's not liking it... Provided that you have your configs right in the Lambda constants (1 and 2), then I bet the reason it runs okay on the NB 02 setting with the WB02 is because it's not using the 02 at all in that case and it's just running off the Injection Map. Recall that the 02 is just there to trim/add fuel to achieve the Lambda setpoint figure, right? If the injection map is even remotely close, the car will run fine with no trimming at all. My car will run quite well with no 02 for instance...
It sounds like your WB 02 is either config'ed wrong at either the hardware (wired incorrectly) or software level (Probably in the constants in this case). What does your Lambda 2 say your AFR is when the WB 02 is in use with the current settings? If your car runs poorly with the WB 02 hooked up, I bet you would be seeing some really goofy Lambda2 readings...
Also did you switch over to Lambda 2 for referencing when you went from NB to WB?
Best,
Phil