Tiptoes vs rubber bottle stoppers: When?

I have a Sony SACD777 that was on one side of setup on a very solid cabinet. Then I moved it to a rack, not so solid. The bottom faded after the move... Tried tiptoes, naaah. Then put size 10 rubber bottle stoppers under feet and WHAM, back comes the bottom stability and "solid" musical bottom end. So??? the question is, what general guidelines does one follow? (besides: what sounds best!!!) and does anyone know the correct amount of weight for a #10 stopper to maximize the vibration dampening properties? and how about a #8 stopper? (I got mine at American Science and Surplus 10's for $1.25 each and 8's for .80...) I use some AQ sorbothane pods under my preamp too.