Discharge of a coil powered by parallel transformers
You haven't drawn a varistor network on the coil, you've drawn a resistor and diode.

Sizing the resistor and diode properly is the key to having them do as you want.

At the point you stop supplying the coil, what is the current? This is the current that will initially flow through the D3 and Rvar. D3 needs to be big enough to handle the current. Although a 1N4007 is rated at 1A continuous, it can take an 8mS surge of 30A. The figures for the 540x series are 3A and 200A respectively.

When this current flows through Rvar, it generates a voltage. Rvar must be low enough resistance so that this voltage stays within your safe level. It must be physically large enough to absorb this pulse of energy without overheating. Not many resistors have pulse handling specified.

If in fact you've drawn a resistor because you didn't have a varistor symbol, then things are a little easier to specify, because a varistor will have pulse handling and maximum voltage specified. Make sure it's big enough to pass the current, absorb the power, and limit the voltage to what you want.