Don - thanks for all the info
Don - thanks for all the info and experience you shared. Maybe I can get a peek at my piston heights by snaking a borescope down into the spark plug holes before tearing apart the entire cylinder head.
I've already replaced spark plugs, fuel injectors, swapped ignition coils, and cleaned the EGR return tube trying to diagnose the cause of the "Misfire on Cyl 2" that I've been getting. Those all seemed to improve the situation temporarily, but ultimately it's come down to missing coolant in my overflow reservoir :(
I haven't noticed significantly white exhaust, but I'm finally starting to see some evidence of coolant in my oil under my oil cap and on my dipstick.