"I'm also not 100% sure I understand the way the wood boards have to be inserted into the bass port. Can you clarify? Does it matter which wood to use and what the thickness of the board should be?"
Suppose the port is 150 mm tall by 200 mm wide by 300 mm deep. And suppose you have access to 18 mm plywood (the kind of wood really doesn't matter - its main function is to take up space). In this case, I would suggest cutting four or five boards, each about 199 mm wide by 300 mm long, and of course 18 mm thick. See if placing some or all of the boards in the port, thus reducing its cross-sectional area, makes a worthwhile improvement. The theory is, if the box is acting like a vented box down in the bass region, this will lower the tuning frequency and hopefully reduce any upper bass bumpage without detrimental side effects.
"Duke, If one product`s purpose is to "absorb" or hinder vibrantion/resonance(attempting to isolate), this is different than "mechanical grounding"(MG). With MG there`s no attempt to absorb, rather you allow the vibration/resonance a rapid and complete exit channel to "gound" this energy into the floor.One seems opposite from the other.An example of the MG approach is the Star Sound system brass points and stands."
I don't see these two approaches as opposites. Your approach addresses mechanical vibration, and mine addresses airborne vibrations, better known as sound waves. One can have a speaker with a resistive port (such as a Variovent, or a DIY variant like I described above), and that speaker can also be sitting on brass points. The opposite of your approach would be de-coupling the cabinet from the floor, via something like Herbie's Big Dots.
I have not experienced mechanical grounding to make a significant difference in the frequency response of a loudspeaker system. From the description, it sounded to me like a large change in the bass response was called for, and so I suggested a possible acoustic solution. Nothing wrong with trying a mechanical solution as well.
Nothing against bass traps or speaker re-positioning either. The more options Amuseb has available, the greater his chances of success. I'm just trying to add to his options by describing a couple of unorthodox approaches that are inexpensive and easily reversible.
Duke