Yes but I've got the stock dummy gauge right off the head, so it's essentially in the upper hose.

What I do know is that I'm feeding consistently coolish (160*) water to my engine.

TTC - Thanks!

I might be totally wrong in this, but I thought it was more important to know the temp coming out than the temp going in, as it would help indicate overheating problems. At the same time, I guess if you were overheating the radiator wouldn't be cooling enough, so maybe its a crapshoot either way.

Right. I'd want to know the hottest temp that the engine is seeing as well.

Conversely, I'd want to know oil temps going IN because the first thing it would see would be the bearings, and I'd want to know it wasn't breaking down prior to that (>300* or whatever).

taking your water temp off the lower radiator hose might be a bad thing

If some routing gets plugged up, thermostat doesn't open, etc. then the water pump will start doing all of its routing through the heater core. The lower radiator hose would still show cool temps - much cooler temps - while the engine coolant temperature continues to rise

Unless you've got your heater core removed, or you're taking your temp somewhere after the mixing manifold, in which case you can disregard :-)

Temp sensor was moved due to routing reasons, I really love the routing of it right now, simple and clean. It was only afterwords that I realized it was a strange location to get a reading. But like I said, I still have the stock coolant gauge, which is reading the hot(ter) water coming OUT of the head.

I know the difference between a 160* and 180* thermostat on my engine, or at least the way the stock gauge reads at operating temperatures. 180* is nearly 12 o'clock, 160* is a needle width below. While I was seeing a stead 160* out of the radiator (easily 150* if I was stuck behind traffic), stock gauge was at or just below 180*, so probably 160-200* out of the head. I feel safe with that until I replace the stock gauge with a real one.