Tonearm mount to the plinth vs arm board vs rotating arm board vs isolated tower

nandric, fo.Q tape is a piezoelectric vibration damping tape that works great on turntables, tone arms, and speakers. Very effective. 

Regarding platter mass, and materials, the differences are obvious and easy to hear. My Miller Carbon turntable is based on the Teres Audio platter and bearing. https://systems.audiogon.com/systems/8367 The design of this table allows the platter to be lifted off and swapped out very easily. 

Designer Chris Brady made four different platters, all identical except for construction and materials. The platters were solid acrylic, acrylic with lead shot, a solid synthetic material, and lead shot loaded Cocobolo. Chris did a demo playing the same music on each of the four platters. It was easy- and impressive- to hear the improvement from each to the next. 

Platter mass definitely does improve dynamics, drive, and bass extension and slam. Going to a stiffer more highly damped material is even better. Each and every one of these changes affects the sound. 

Try the tape. Its cheap. You'll be surprised how well it works.

Yes.

Of course there is a difference. For what you are doing though the most important considerations are flexibility and ease comparing several different arms. The best way to do this is with an arm board you can rotate to easily accommodate any length arm. Also if you need different hole sizes this is the easiest way as you can make several boards identical in every way except for the hole. 

This can all be done fast and cheap because its really only for comparing. It will be more than good enough to compare. Then when you know which arm you want it can be mounted in the plinth, or on a better more finished looking arm board. 

Another thing you can do along the way is make some arm boards out of different materials. Set up right, like with a notch in the boards, you could change them out so fast and easy it will be no problem to compare several. MDF, acrylic, different wood species, you can try easily and see. They each have their own characteristic signature sound and this will enable you to tune for the best result with your final arm choice. This is a far better approach than what most guys do trusting someone else and then paying them a lot for something they have no idea what it is.

This will also teach you enough to know whether you want the arm on a board like this or in the plinth, or inlay mounted in the plinth. In other words router out an area of plinth and inlay your arm in that. Either this or the rotating arm board are great ways to have a good looking table that can easily accommodate a range of arms going forward.