Typically in Panzerholz the B25 Type Material is used which is a 25mm Thick Board with 25 Plies per 25mm.
More recently I have seen lesser Thicknesses used and only once seen a Thicker than 25mm used which was at 32mm.
The individual in the UK who was instrumental in bringing P'holz and Permali to the forefront as a Structure Material, made it known 10mm was the thickness that was generating the ideal damping / dissipation measurements. It was made known additional Thickness was not going to improve things. That is not to say an additional thickness is without attributes, the sonic is known to be effected using different thicknesses. I have a Permali Board at 75mm Thick, to one day become a Plinth Material, but not a conventional design.
From my end, if a Thick Plinth is required for aesthetic purposes, there is the option to add a Perimeter Skirt to the desired dimension.
A few years past I was to have a few experiences of a Garrard 401 mounted on a Highly Compressed Bamboo Board, that I know as a material, is not too different from Densified Wood measurements. The Demo' of the 401 from the recollections of past experiences at the time, was from my assessment the best I had heard from a 401.
The Bamboo Board material is one that can be looked at as well, especially for Idler Drives, this is also to be seen on LH as a Plinth Material.
Note: There is something quite special to be experienced when using a Sub Plinth made from a Resin Impregnated Densified Wood Board in conjunction with TT's Plinth. Separation Footers will also add to the fine tuning the sonic, there are plenty of trials to be had with footer used under a Sub Plinth and used as a Plinth Separator.
