Hi Haddock,
Personally I have several psi whell. Small paper, aluminum, cardboard, tin above. My smallest are less than 1g and my biggest card in 16gr and 20 cm. I always start my practice with a little warm for me. If it turn easily so I'm taking a larger and heavier psi whell. If I have trouble turning a simple little piece of alumium paper, so it is useless to try with my whell psi 16gr. But I practice anyway because you can practice even with a simple little piece of aluminum foil.