SOTA, soft feet or cones, when to use either?

Hi all,
My SOTA is on soft stock feet now but I have the metal cones aswell so I want to know when is it best to use rubber or metel and how do each affect sound?
For the "record" I am in a dedicated basement room and my table sits on a Tsrget rack with a sort of suspension shelf. Thanks for input.
P.S. I know I could try it and see what happens when changed but due to disability it isnt as easy as that............thanks!