So I have placed these silicate packages in my roadster in several places in the fall and while storing it for the winter.
I have some in the rear wheel wells, along the floor, ashtray, under the dash near the guages and along the windshield vents, I placed additional ones throughout the engine compartment (I pull the ones that might get hot when I fire up the roadster).
So far it has worked like a charm pulling the moisture caused even by my breathing and any stray moisture that creeps in with me on my boots etc.
I am using the big ones that are 3"x 5" but I also have bundles of the smaller ones placed in mesh bags for the wheel wells.
BTW put some of these in your refrigerator in the veggie tray and your veggies stay fresh substantially longer (but don't eat them

Hope this helps others.