I found that not all footers of a type (squishy, roller, rubber-like, hard, wood, spikes, etc.) work equally effectively in all spots. It seems that some types of equipment react better to one type than another.
In my experience I found squishy things under tubes and roller things under solid state and power supplies. Spikes under speakers. As for my CD player I have an Ayre and use the Ayre myrtle blocks, which are no more than small blocks of wood. For the turntable nothing beats mass and more mass, but I do have it sitting on a butcher block and have found putting about a dozen squash balls between that butcher block and the shelf helped quite a bit to reduce any kind of taps on the rack or footfalls.
But then, that got me the sound I wanted from each. If you want to tighten things up maybe you want spiky things under everything. If you want to soften, use squishy things. It's all to taste.