Proper length of load bars on roof rack

[delta447]

Hi everyone. I want to add a Thule roof rack system to my wife’s 2011 X5 (Premium model). When I used the fitment guide on rackattack.com, I was advised to go with either the standard 57” load bars or the premium 53” load bars. I measured the distance between the two racks and it is only 43”. I know that I can get shorter standard and premium load bars that won’t stick out so much on either side of the vehicle. I have also looked at other X5’s on this forum and I don’t see the load bars extending very far over the factory railings. Does anyone have an idea of what length load bar works best on the X5? Thanks in advance.