Modelling a transformer in LTspice
I personally use a simple dc transformer constructed with a current-controlled current source (\$F\$ primitive) and a voltage-controlled voltage source (\$E\$ primitive). If I am not mistaken, this circuit was introduced by Larry Meares from Intusoft some years ago, circa 80's. See page 114 of this document published by Intusoft for more details. The dc transformer can be used in a variety of applications, including switching power supplies cycle-by-cycle simulations or average modeling. I prefer the version in which the leakage inductance clearly appears as it is easy to modify while a coupling coefficient needs extra computation to extract the leakage term. The below drawing shows the equivalent constructions between a coupling coefficient and the equivalent transformer.



The parameters window in the right-side of the drawing tells you how to calculate the leakage and magnetizing inductances from the coupling coefficients. After the simulation is run, the output voltages and input currents are rigorously identical.