Vortec coolant bypass question
 

I have a Ram Jet 350 that I just got running for the first time a couple of weeks ago.
However, this question would pertain to any vortec engine.

I am getting wild fluctuations in water temperature right when the thermostat opens which I just learned is due to not having a coolant bypass.

So my question is, what is the best way to achieve this and how much flow is needed?

Should I drill a couple of small holes in the thermostat?

Or, should I install a bypass hose from the intake manifold to the water pump?

What have y'all done?