Question: Is it possible to model a plate thinner than 1/16"?
Answer: To model a plate smaller than 1/16, go to File > Settings > Options > Units and Decimals and adjust the Section dimension under the Catalogs tab to be a decimal inch. You can also change the number of decimals if needed.
Keep in mind that when you change the settings back to ft-in, the plate will show up as either 1/16" or 0" under the model's properties. However, if you measure it in the model or in drawings, it will be the right thickness. In drawings, you will have to change dimensions' precision from their default, 1/16" dimension.
If you modify the plate after you switch the settings back, it will also adjust to 1/16". In short, though this is possible to achieve, you have to be aware of the fact that working with the plate afterward means you will have to adjust the Options back and forth.