Matter of preference. I dont like silica, use cottom BioWick. Friend of mine uses cotton only im drippers and prefers hollow ekowool in his kayfuns. Some just like plain silica. Try them out and see what you like best. Potentially i would see the hollow being better as you only need
juice at the coil but then yourr getting less flavor "fumes" from the unvaporized juice soaked im like a protank "flavor" wick. Just try them all
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