Dear Kftool: I don't know which one is your first passion: music or build the hardware to enjoy music.
It is clear to me that no one goes with your dedication ( DIY ) to build audio items with that in deep passion if does not has an in-deep passion for the music.
I applaud that passion, go a head!!!!, we came to this " world " to be actors to transcend: good.
Now, as a DIY you don't have all the answers ( the right ones ) to your TT project and that's why you are asking about.
I can't help you because I don't have the precise answer you are looking for but if you permit me the thread bring to me some thoughts on the TT subject.
This is not the first thread where exist a dialogue about TT plinth, many threads on this subject with out any single precise answer: only people talking and talking and talking with out clear, tested and precise foundation. This has a name: charlatan ( in spanish this is what is a charlatan. ), and this include me.
I know that many of us that are not professional and commercial TT designers do not have the knowledge to give the right answer not only to your question but to almost any other TT question but exist in this forum the TT Pro that I respect but that does not have the right answers either.
That answer that was posted here: +++ Go with your best judgment based on research and common sense. ++++
not only does not help but IMHO means nothing.
This is not a " common sense " solution, we need science/enginnering knowledge here. IMHO through science and the precise/right know how on how apply the science/engennering you/we can have the answers you/we are looking for.
Unfortunatelly no one of the TT Pro ( Caliburn, Monaco, Walker, Teres, VPI, Rockport, AS: just name it. ) or any one else has a scientific tested answer to your question. No one ( at least I don't read it anywhere. ) already find which TT vibrations/resonances are pick-up by the cartridge and through the tonearm to the cartridge. Which TT vibrations/resonances ( it does not matters where they come from. ) could mean: at which frequencies, at which level(spl), which kind of vibrations/resonances affect the most and how, with which build or blend materials: at the plinth, platter, arm board, footers; a high mass is the answer? where are the scientific studies/tests that can prove it?. Lead, slate, carbon fiber, magnesium, the best TT build material? where are the scientific studies/test that prove it? and I can go on an on with no answers, only " common sense "??????
As I say this is not a " common sense " subject: you/we have to apply science/enginnering research with the right scientific " tools " to have answers with foundation where there are no place to doubts and/or " questioning ".
Till today IMHO and with all respect to everybody we only have or are: charlatans on the subject.
Regards and enjoy the music,
Raul.