Continued use of lambda is expected, I don't know of any reason to ever turn it off.
Some level of fuel pressure correction is already in the Reflex+ but not being used unless you add a FP sensor (or we have enough time to find the fuel pressure PID) On my 2015 C7 the fuel pressure on the CAN bus is quite intermittent (as per HP Tuners) so I simply installed a fuel pressure sensor at the fuel rail feed using the components below.
https://toohighpsi.com/products/refl...ensor-0-150psi
https://www.amazon.com/EVIL-ENERGY-P...2s9dHJ1ZQ&th=1
The sensor plugs directly into INPUT 2 on the Reflex+ and will let you log / correct based off port rail pressure. There is a "Fuel Pressure Factor" table and I am working with MOTIV to verify/rewrite this to be differential pressure (FP - MAP) that way we can simply input the flow data from the injector manufacturer directly.
I don't currently do any injector correction based off fuel pressure - I primarily use the fuel pressure sensor to set the duty cycle of my aux pump to maintain the commanded pressure in the E92.
Lots going on in this plot, but I'm commanding 55psi fuel pressure in the E92 and its maintained fairly close by the stock pump plus the Reflex+ PWM control of the secondary pump. The PWM allows the system the avoid the spike of turn on like is normally seen with simple secondary pump control systems.