Some updates,....

I ended up use a 0.5 mm strip, a 1.0 mm strip and a 1.5 mm strip of thermal padding.

The ssd controller to the copper thermal sink (1mm) used the 0.5 mm thermal pad, the ssd storage to the Cu heat sink used the 1.0 mm thermal pad. Then the Cu heat sink to the metal chasis used the 1.5mm thermal pad.

My SSD temp is 37.9 C on idle and under load it only gets up to 43-47 C.

It worked out REAL well.

As for the thermal pads I used GELID's 15 WMK, there were other thermal pads rated at 18 (Fujipoly etc) but the cost was 3x and really for an ssd using the chassis as the heat sink I do not think it was worth the cash.

In total it cost me about 50$ for the materials, the installation was without issue and I am REALLY happy with the results. Previously it would hit 70+C on full load and then go into thermal throttling, I have not come CLOSE to those temps, it has never broken 50C.

FYI links to materials: NB: I did not buy the materials on Amazon I am using Amazon links as references for others only.

https://www.amazon.com/Gelid-Solutions-GP-Ultimate-90x50x1-5mm-Installation/dp/B0922H5X1Y

https://www.amazon.com/s?k=fujipoly+17w+thermalpad

https://www.amazon.com/Laptop-Heatsink-Thermal-Pads%EF%BC%8CHeat-Copper/dp/B07YC1HTFR

You can try with the stock thermal pads that the Cu heat sink comes with, I figured that since I had no idea what the material really was it was better to spend the few bucks to get known values for the thermal pads.

I hope this helps others.