Sorry to revive an old thread but I installed a Defi Oil pressure guage recently.
The pressure sensor is located on the top gallery to the left of the AC which reads ~10psi lower than the stock pressure switch location.
Anyway, doing some testing this morning, I was seeing ~5BAR (~70psi) from 5-7.5k rpm with oil temps at around 100-105C (212F - 221F).
That is significantly higher than the ~43psi @225F you measured. My car is completely stock except I am running 0W20 Millers Nanodrive Oil.
I know the oil cooler can knock around 14psi off the pressure at higher temps but 27psi difference
Where are you measuring oil temp? Im using a ODB reader to get oil temp from the stock sensor.