I used one very thin washer at the back center near the leveling screw. I added the thermal compound on most of the surface, but realized that the center is the only place that really needs it.
I used 3 binder clips, one at the back right over the washer, 2 on the front edge. This keeps the clips out of harms way, and holds the glass secure without putting any bending pressure on it.

Leveling was much easier as the glass was flat in all directions.

I sprayed with hairspray and started printing.

Results were good, much better than warped bed and kapton tape.

The bed still needs even heat across it, all the way to the edges to be perfect, but I am satisfied.

The thermal compound I know about would likely cause quite a mess once it was heated.  And it is useful to be able to take the glass off, either to swap a new piece in for the next print, or to put it in the freezer to help tease a part off.

Binder clips cause the glass to warp as bad as the aluminum.
Magnets and plastic brackets may have alignment issues if placed on in a different orientation.
Heat transfer from aluminum to glass is not optimal, only a small portion of the glass comes into contact with the original bed.

Here is an idea I am going to try, hopefully someone with more experience or knowledge than me can comment on them.

My bed is warped, the center is the high point. The glass can't be reliably positioned as it teeters side to side like a see saw.
I am going to place small spacers, maybe only 0.3mm thick on each corner so the glass is resting on the spacers not the high points of the bed.
To fill in the gaps, I will use thermal compound. Thermal adhesive is also an option but you can't go back once it is attached.
With the glass resting on the spacers, and the thermal compound filling in the gaps, binder clips can now be used to pinch the glass to the bed. I will place them on or near the spacers to prevent any warping of the glass.

The glass is guaranteed not to teeter while resting on the spacers. It can be removed if needed.
Heat is evenly conducted to the glass.

Let me know what you think, I will try it out by next weekend and let you know how it goes.