How is a Thermistor supposed to be installed between Heated Bed and the Glass? opposed to what the title of this question might impose, I'm not new to 3d printing itself and have operated more than one printer for years, however, I feel dumb with installing the Thermistor on this new Heated Bed I got from RepRap.me: Aluminum Heatbed MK3 400x300

The old Mk2b 214x214 Mendel/Prusa heated bed that I have been using for quite a while now has a through-hole in the center, where the thermistor-leads could be fed to from below.

On this new heated bed however, there is a lowering in the very center of the Heated Bed to place the Thermistor in, yet the pads to connect the thermistor leads to right beside it are level with the rest of the Heated bed.

I tried using just a tiny amount of SMD solderpaste and just soldering the thermistor leads as flat as possible to the pads, nevertheless, the glass plate on top is not laying flat and stable on the heated bed with the thermistor installed.

Any suggestions are greatly appreciated on how improve the thermistor-installation onto this heated bed!
Try to use a silicone heat conductive pad between heater and glass, where you can make a hole for the sensor. It also helps to improve the contact between aluminium heater and glass, which otherwise may be inhomogeneous (as expected between two quite rigid materials).

They sell them in rolls and you can choose a 1 mm thick one or even 0.5 mm. They are "sticky" but they don't have glue, so you will be able to separate the glass from the pad, even if not so easily as it would be with a clip.