Another way to do it is by using narrowband feed from zeitronix or innovative (it if supports that). I have zeitronix and I know that you can program it to skew actual readings towards either lean of rich by a large amount. Zeitronix then is wired in place of O2 sensor and ECU thinks it is using actual o2 narrowband sensor while it is actually zeitronix that is feeding it the data.
The setup of the new stoich is called "Switching point". You can set it to anything between 9.7 to 20.7 ... so you can choose your new stoich and the zeitronix will be simulating happy 14.7/1.0 sensor while in reality it tell ECU to stick to your chosen value.
I have no need to do any schenanigans like that but since you do.. maybe you can pioneer the way for rest of us
