The two different Fisual stands are very different heights. They're about 40cm different. You want your speakers (ideally) so the tweeter is at approximately ear height when listening. The first ones are quite tall and, I would think, more suitable if you're sitting at a desk or table. The shorter ones look a better height for listening when on a sofa or armchair...
Regarding the plate size: You don't want it bigger than the speaker, and you don't want it massively smaller - the speakers can get a bit unstable. Otherwise, not that important to match the plate size exactly. For reference, the plate size on the Q3000FSi stands , made for the 3020i by Q-Acoustics is 250 x 290mm (and they're 682mm high). The Fisual Dynami has a plate of 165x200mm - so quite a bit smaller.
I must admit, mine are just sitting on shelves on my Billy bookcase, and they sound great...