I have the same truck with the Andersen hitch , I use the adapter putting the fifth wheel closer to the cab ,no clearance problems . I had concerns with the pin box hitting the tailgate so the reason for the adapter in that position . Prior fifth wheel had the adapter the other way around putting it further from the cab ,no issues with that either . All depends on the pin box .
Can't answer about the gooseneck connection ,I have the steel Andersen . It's mounted to the rail adapter attached to the puck system , its puts the ball slightly rear of axle center , so as far as the ball being back that's not a issue with towing .
I have towed with the Andersen now for several years ,wouldn't tow with anything else .My son also tows with the Andersen , the aluminum like yours , short bed Superduty ,no issues .
