Microwave Assisted Magnetic Recording (MAMR)  is a novel technology developed to extend the areal density growth of magnetic recording. To achieve higher densities, grains with larger anisotropy and higher thermal stability are used to store the data, in order allow the grain size to be reduced. But this comes at the cost of the grains becoming more difficult to write, especially as the write head shrinks in proportion. At the time of writing with MAMR, an assisting, oscillating high-frequency (HF) field is applied, typically from a spin-torque oscillator (STO) that causes the grains to resonate, reducing the amount of write-field needed to switch the grains. In 3D-MAMR, this principle of magnetically resonating grains is also used, but in this case, in addition to assisting the writing of smaller high anisotropy grains, it is used to select a specific target layer for writing in a 2-layer recording system . In this work we optimize the media parameters in a multi-layer media stack in 3D-MAMR with 2 magnetic recording layers (RL), each recording layer having a hard and a soft sub-layer linked through exchange-coupling as shown in Figure 1.