I don't do vinyl but I do physics. So as I drink my morning coffee, here are some thoughts on the theory behind it that might help you in your journey.
On speakers I generally recommend springs rather than spikes since springs isolate the speakers from the floor at let them vibrate with the music like the musical instrument that they are.
On components, many people put springs under them to isolate them, the thought being that the rack, floor, or room might be vibrating slightly by the music (they must be playing loud). Generally, I think this is not going to achieve much but I'm sure sometimes it does.
On a turntable, you have a different situation, your stylus IS vibrating, excited by the spinning disc. So you don't want other vibrations sneaking in there. Isolation with springs is an option which will stop vibrations from coming into the turntable from the rack.
As for butcher block, my first thought was that springs would be better. But thinking about it more, buther block could have more effect. if you anchor your TT to the butcher block with spikes or solid feet, you are adding much mass to the TT system which changes it's natural frequency, likely out of the range of interest [f=sqrt(k/m)] so adding more mass will move the natural frequency more. so thicker butcher blocks are more mass.
Now you are adding isolation springs on top of the butcher blocks which negates the value of the added mass. In fact, it mostly relegates the butcher block to an aesthetic treatment. It does raise the mass of your rack, thus changing its natural frequency, but is probably less heavy than the other equipment on it--the exception would be if you have a relatively light rack with just the TT on it.
Jerry