Anyone running an oil filled gear diff? If yes, what weight oil are you using?

I've searched back and found a few references to the 3racing diff, mentioning that the kit oil is way too heavy. Someone put 30wt in, but I couldn't find any follow ups.

And a big thanks to Raman. I copied the setup you posted and my car was easy to drive (almost perfect). I'm hoping that a slightly thicker rear diff might help with braking.