I just checked mine and there is a paper-thin gap on the passenger side, about the same as yours, maybe a tiny bit less. I never noticed, you won't notice it with the rack mounted.
The gap on mine is quite wide. Can probably fit 2-3 credit cards in between. I contacted Westcott and they said the cross bar behind the visor wasn’t cut properly where it is longer than the visor. Trying to find a solution with them
Can you just move that crossbar to the middle of the rack where the gap won't be noticed? It's aluminum....you could always sand or grind it down a bit.