Full glass hotbed conversion

Please, read and understand everything before you do anything.

Skills needed: hand cutting and hand drilling aluminum, basic soldering, basic gluing.

I was very tired of how uneven aluminum plates was. Cast and cnc-ed aluminum is very expensive and hard to find. Also, since my printed has a moving bed, I am always finght the bed weight. Most people use aluminum and then put glass on top. Too heavy. Some just use heater plate as a base and clamp glass on top. Okay for not moving bed, but too flimsy for a moving one.
So, I though why I need the aluminum bed at all? Just for the screws? Then let’s find way to screw the glass the carriage and not even damage the top side of the glass.
Usual window glass is no good. Maybe even maybe not. So, I tested the method on usual glass and then used a 4 mm mirror. Mirror is good because it can be visually controlled for any distortion. Eye is very sensitive instrument, can see holes up to 0.01mm and detect very small distortions.
Using a mi