thank you for the link and yes i will take off the coating from the fets (i knew i ll had this comment as i posted the pic) , it is easier to take off with a bit of tickness and it looks worse on the pics
for the pad , yes i will avoid carbon and graphite, not sure what to look at for none conductive : “Dielectric Breakdown Voltage”?
tickness: something for 0.25-.5mm, oem looks hard and probably" dry out", may be i would try 0.5mm around 20-25 shore
I don’t think coating is the right thing. All those tiny vids around gets are there for better heat dissipation and yes even very thin layer of coating will reduce it. Plus solder mask coat doing the same thing and It is not possible to make sure all exposed pins are coated 100%. What I did to mitigate potential leakage was to fill the box with silicone mix so it fills all gaps around the boards and the box plus it has some thermal conductivity to help dissipating the heat. Maybe there is on out there with higher thermal conductivity:
