The way you’re doing it will only drive you crazy. The reason is because the whole turntable/arm/cartridge/shelf system is vibrating. You can talk about any one individual part, change any one individual component, and hear a difference and know why- because it was just the one thing. So if you for example build a couple different bases or arm boards and change them out keeping everything else the same, fine. We can talk about that. You can evaluate that. But that’s not what you’re doing. You’re saying plinth but talking about whole complete different turntables. Which is a whole complete different thing. Right now you are asking about completely different turntables with completely different bearings, motors, platters, on and on, then trying to zero in on the type of wood, as if none of that other stuff is going on. Drive yourself crazy, and everyone around you too.
Check out my system.
https://systems.audiogon.com/systems/8367 I built that. The rack, the table- and not just this one but what you don’t see, a bunch of prototypes or trial efforts or whatever you want to call it. I’ve heard the same components (bearing, platter, etc) with only one change (plinth, arm, motor, etc) one at a time. Not only on the Miller Carbon but on a Basis table before that. I guess you could say I kind of have a clue.
Two things I can say based on your question. One, forget your current approach. Forget asking people here for advice. Look for turntables you can afford, and when you find one search out all the reviews. Buy based on those reviews. Or Two, do like I did and get yourself a turntable constructed in such a way as to facilitate modifications. Something with a simple base you can build yourself using different materials. There’s general things you will learn, like every material imparts its own signature sound. Which is why laminates are so common. Laminating materials together averages out the good and bad of a lot of imperfect materials. Awful lotta work for a table for a office. I would go with the first one, and start reading reviews.
Take your time and don’t stress because no matter what at the end of the day you will have a turntable, and it is pretty hard to go bad when you got that going for you.
