Audio Tekne carbon blocks

Please advise as to the best way to utilize these blocks. Can they be placed on top of component covers over the transformers if covers are to be left on?
I think normally these are used as footers...but as the similar ART/Yamamura Q blocks, these can "suck-up" vibration anywhere you put them. I would not put these on top of the transformers, as this usually kills the sound...
The AT carbon blocks are very good footers as Prcinka stated. I preferred them over the Goldmund cones (softer presentation). The Shakti stones work very well on top of transformers, not to absorb vibrations, but to deflect RFI/EMI .