@Blue-Truck-Nut
Am not familiar with storage space on Coupes. No room behind the seat, or in the trunk/rumble seat?
For certain spares I like to keep fresh (like a spare carb) I use zip lock bags with the slider zipper, and desiccant bags. Then put that in a bubble pack bag that seals. The place I worked for shipped spare electronics to our techs, so at the time the bubble bags and desiccant was easily available to me.
I make sure the carb is dry, run it out of gas, drain it, remove it, split the carb halves, remove the float valve, turn it every which way , and with low pressure blow it out, apart let it sit in the sun for a while, blow it out again, and then reassemble it. Yes, am a little anal at times.
If using desiccant bags, was told to keep them in a cool low humidly environment so they would be dry/little moisture absorbed. And is best if the parts/bags are also in the same low humidity environment when packing the part.
Was talking to one of a fellow club member who told me he uses baking soda and very small thin paper bags, uses a needle to poke holes in the bag, to make his own desiccant bags. He tested by putting metal and his homemade bags in a Ziploc bag. Then stuck it in the fridge, and then in the bathroom when showering - no moisture in the bag at any time.
3rd Brake light - the one I used, even though I did not use them, came with suction cups for use on the interior of the rear window. I think there was a couple of short standoffs and long screws with nuts - this would require drilling holes in your A. I like mine on the tailgate of my truck - I think it is more noticeable, Leds seem to be brighter when seeing them straight on than viewing at an angle, and are more at eyelevel of people following you.