is there anyway we can read the amount of oil in the RIG instead of expected oil per second?

I second this, would love to be able to read the contents instead of the oil p/s

There was always a little GUI box with the stored oil amount that popped up on the top left of the screen when you open an oil rig GUI.

In the latest update, this GUI is attached to your inventory when the oil rig is open so it is more obvious.

I'm pretty sure they meant when attaching a circuit network connection. It would be super helpful to have the oil rig contents linked to an LTN stop for that oil rig, so you can send the tanker only when the oil rig has enough to make it worth it.

I started playing with doing this myself for a bit, but I currently have too much to do to actually continue it. Maybe in a few weeks. Unless if somebody else does it before me. How I thought to solve it, was to add a constant combinator that was built automatically, and then some onTick code to update the signals in that combinator.

Good point, I forgot you could even do that with pumps. We'll look into it. The oil rig already has several dummy entities so it would be simple to add another.