Due to the low front height and 6 degree angle, the maximum weight thickness I can achieve is 2mm. It is placed directly under the alphas and I feel that it has really helped with the sound.
There is a spacebar cutout in the bottom case for screw-in stabilizers so you are not limited to using clip-ins only. Please use clip-ins for backspace otherwise the oring would be pinched against the case wall and the plate.
If, for whatever reason, you like shaking keyboards; depending on what stabs are used you could potentially feel the build move slightly in the case. This has no effect on the assembly of the case or the actual functionality of the keyboard.