Hi, imf22. For the DAC, I recommend four TenderSoft Tenderfoot isolation feet underneath and a SuperSonic Stabilizer on top. For the turntable, six 1"-diameter grungebuster Dots between the maple block and shelf (or Extra-Thick grungebuster Dots if you have any macro-vibration issues like footfall).
For the phono stage, four TenderSoft Tenderfoot isolation feet under the chassis and a HAL-O III-9 Vacuum Tube Stabilizer for each of the 6H30 tubes.
For the amp, an UltraSonic SS-9 Damping Instrument for each of the small-signal tubes and a HAL-O III-50 (or other appropriate size) for each power tube. Also, four Extra-Firm Big Tall Tenderfoot isolation feet.
Sanus has lots of 4-shelf rack models. One of Herbie's dBNeutralizer-based products between the bottom of each of the rack legs and floor will make a superb isolation/decoupling interface.
(Cork/rubber blocks are cut from a generic construction material, not an audio product at all, and is sort of a junk material when attempting to use with hi-end audio.)
P.S. Sorry about not replying to your post sooner; I didn't know about it until now.
Herbie's Audio Lab