As others have mentioned, there is no way to predict the sonic result from changing racks. It would at least be easier to make decisions if certain approaches always improve the sound but that is not the case. I have heard exotic shelves do exactly as advertised -- dampen and reduce vibration -- that sound great under one component and sound like crap under another.
My suggestion is to go with a very good, solid and stable rack that is presentable in your room. I would also focus on whether one with fixed shelves or one with adjustable shelves is what you need. Also, some racks and some makers of shelves have products that allow for mixing of shelves from other manufacturers. For example, Zoethecus (unfortunately defunct now) racks could use standard sized Symposium shelves. Some manufacturers of shelves also make custom sizes so you should also consider how well a rack would work with such products. I would consider building in a substantial extra margin of vertical spacing to account for the possibility that you will be adding in a custom shelf or couplers, etc.
After you get a good basic rack, you can then experiment with different shelves and couplers and other tuning devices. Good sound from support structures is a matter of "tuning" -- there is no one right approach and right sound.
Good luck.