It is good that you are thinking in the future failure analysis mode. I would recommend, rather than your plumbing plans, that you ensure you have a good quality, functioning oil temperature guage. Oil pressure doesn't hurt either, if it's a good one you can actually schedule your oil changes off of it's readings. Oil, not water, does the majority of cooling in your engine and all engines. Your first indication of trouble will be rising oil temperature. By the time you see rising coolant temperature your engine has already been stressed, if not worse.
Now if you really want to do things right, you'll also install an idiot light. The reality of guages is that we never are looking at them when they're telling us something is about to go horribly wrong. We're busy running aground or some other important maritime adventure. The idiot light, commonly used in racing cars-refuting it's name, should be hooked in to light when any of your guages are out of "normal" range. It's installation requires different sending units for each function monitored. It lights so as to draw your attention to the guages.
A solution short of this, and cheaper, is to mount your guages in a fashion that all of the needles are either horizontal or vertical when in the "normal" range. This is another race car design technique. You don't really need to "read" the guages; you just need to know they are in the "normal" range.
While on the topic, I am a big fan of VDO brand guages.
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.