There is actually a reason why it is sometimes done this way around. If there is a leak in the cooler, instead of water being pumped into the oil, the oil is more likely drawn into the water. Not sure which is worse, but neither is a good thing to have happen. I have the pump first and the engine oil cooler second, the transmission
cooler third, the water cooler fourth and the manifold last.
Any opinions on the real value of knowing engine oil temperature - ie. will this be an additional gadget with minimal practical value?
No not really. Not for small engines like we guys play with anyway. The water temp tells you all you really need to know.
By the way, the oil does about 40% of the cooling
, the water does mostly the rest. A small percentage is air cooling