How thick is the limit?... never heard anyone say?

I have been looking to buy very thick- 3 inch min to 4 inches thick, Amp stands for years. I am not a big "amp stands are the keys" to better sound person. I just think that thick wooden slabs look good, I have no idea why- but I guess it must be a man thing.
Clearly turntables and digital front ends benefit from mass. Amps however, I doubt benefit terribly much. Just being honest, but the amps are tubed monoblocks so the stands may cut down on the non existent microphony. Couldn't hurt ....right?? ...I hope.
I got lucky, knock on wood!, because a buddy is selling amp stands as if I custom ordered them.
My question is- Can the wood be so thick that it makes the amps sound worse?? In this case they are 3+ inch thick edge grain, audiophile finished natural Maple, block.