Replying to Upper body direction when sliding rails/boxes

i'm a beginner in the park, and i've been learning to slide boxes on a summer setup for the past month or so. i seem to have it down pretty well, so i wanna move on to sliding rails. for some mental prep, i watched a few videos for rails vs boxes and there seems to be some disagreement about whether or not to point your shoulders/upper body down the length of the feature. the way i learned it is to face down the feature with both my head and my shoulders with my arms out to the side, and now i'm starting to think that i learned it the wrong way. what do you guys recommend?