It will work just fine as is. I was only pointing out why the temperature appears to spike with the valve closed. I have never owned a truck with the fancy heater bypass. The only ones I have worked on in other vehicles were three way valves. This allows the coolant to flow even when the heater core was bypassed.
The reason I prefer a loop is that if the thermostat sticks closed and there is no loop the temperature will rise and you will be used to it rising. By the time you notice something isn't right there is a good chance damage has been done. On the other hand, if you are used to the temperature always stopping when the thermostat opens you will be more likely to notice if it continues to rise.
