XPS 13 (9350) Thermal Solution Upgrade using Thermal Pads & Paste

Hello Guys,

Recently, my dell XPS 13 had some heat issues when running a lot of task (gaming, video editing, etc). The CPU package temp ramps up between 96-99 C and starts thermal throttling which slows the performance of my PC. 

So I came up to solution which I found on some forums and on YouTube tutorials. These were undervolting, thermal paste replacement and themal pad application for the CPU.

I downloaded Intel XTU and wanna perform undervolting but the “Core Voltage Offset” tuning section was greyed and i was not able to adjust the voltage offset for undervolting. 
Is there any reasons for this why Intel XTU cannot allow for this? I know my laptop cannot be overclocked but undervolting should be okay.

Also, I ordered Thermal Paste & Pads for my CPU and applied it using the Youtube tutorial. I have divided and put all pads around the heatsink area all the way to the Radiator. The 1mm thick pads were almost touching from the backplate. 

After the upgrade, I have stress tested the CPU and it was doing great than I expected. My CPU package temp could only reach around 75-80 C which is really good. I was amazed by the Pad & Paste combination to reduce the generated heat.

Now the problem I am facing is the heat transfer to the aluminum backplate of my XPS 13. I know that the heatsink area side is not close to the battery but is there any significant issues that might happen due to this heat transfer to the plate?

Which other areas do i need to apply thermal pads to reduce generated heat?

Any suggestion and advise would be greatly appreciated.

Thanks.