[danb35]

Thanks for your suggestions. Some of them may be implemented in next releases.

Does that mean there isn't any way to configure these at present? That's a little surprising, though it would certainly explain why I couldn't find it...

But not the quantity of water it represents.

But you aren't measuring quantities of water (liters, gallons, whatever)*--you have no way of telling how many liters of rain have fallen, because you don't know that the rain rate is constant over any particular area. I'm in the US, of course, and I'm not at all going to get dogmatic about how units are expressed outside the US, but the "/m^2" just seems like a meaningless qualifier. In the US, rain is measured in inches, without any area denominator.

* Strictly speaking, you're measuring the quantity of water that passes through your rain gauge unit, but that's of interest only as a means of determining mm or inches of rain.