I still had your PVoutput in a window from yesterday and was looking at it this afternoon thinking “that cloud is ruining a perfect day”.
Be advised that your total voltage may not be exactly double the single leg voltage. It is probably very close but unbalanced legs can cause differences. I run my home IoTaWatt with a 230V Euro transformer plugged into the 240V and calibrated down to half. So I can legitimately double it for the grid voltage.
I have been doing this since 2019 and explain my reasons in this post:
Your PVoutput is looking much smoother now. I can see that you are oriented pretty much directly south and I can see where the sun comes up, where it begins to shine directly on the array, where it falls off the array and when it sets. I was pondering that knowing the location, it should be possible to compute the orientation of an array. Or conversely if the orientation is known, compute the longitude.