Trying to tint the "glass" on any kit might best be approached with very light coats of any transparent colored paint. I have had fairly good results with very light dust coats of paint applied to the inside of the glass part. After masking the outside surface to prevent any overspray, I'll give a very light dusting on the inside mainly along the upper edge for an OEM type of tinting and a more even coat for something like a gasser. Waiting for a second or even a third coat after the first coat has setup. With the outside surface masked you will be able to see how dark the tint is getting after each coat by looking at the inside surface. Depending on the desired finish the glass can be dipped in Future Floor Wax to seal the color and add a high gloss to the finished glass.