If you don't want to add much filler or weight, and don't want to play with glass, you could drill into the CRs from aft, to create a channel to get in from the inside. Make the hole large enough to slide a section of tube into, atleast say 1/2" or larger if you can.
Get some water balloons, and seal them to a tube that is attached to a bicycle tire nozzle.
One inside the other for durability, then a small section of aluminum foil to protect the contact balloon.
Stick this second, inflating tube, into the placement tube, having marked depth and the like in the design phase of said contraption.
Basically, get the balloon up there, then inflate it to push the tube out from the inside.
You can carefully decide how much balloon you will need, and cut the placement tube accordingly. Slot it, so the balloons and foil patch only expand into one radial direction.
The other option is to drill tiny holes in the damage and pull the dent out carefully.
A compromise of both methods would probably work too, but there are many creative solutions to this dilemma that are worth doing, versus not doing anything.
When it is pulled into position for repairs/glue, that's up to you and the others, as you said you don't want to use any FG methods.
