I store a lot of my filament spools inside vacuum storage bags. I include a perforated canister of silica gel inside every bag, along with a hygrometer. My usual cylinder (which I use inside my PrintDry vacuum tubs) is awkward in vacuum bags, so I designed a new one that fits between the sides of a typical 200 mm (1 Kg) filament spool.
I've included 2 version of the canister body, 1 with 1.2 mm holes and 1 with 1.5 mm holes. I would try the 1.5mm hole version first. If the silica gel can get through the holes move to the 1.2 mm version.
I print them using 1.4 mm layer height. I use clear filament (PETg in my case) so I can see the condition of the silica gel more easily.
My silica gel cylinder: https://www.printables.com/model/659372-silica-gel-ventilated-cylinder
PrintDry vacuum tubs: https://www.printdry.com/product/vacuum-sealed-filament-container/
UPDATE: someone requested a version that will work with 200g spools, I've added it.
The author marked this model as their own original creation.