[EdZ]

everything else being equal (lever length, speed, accumulator load/release, rhythm) yes, the heavier person has an advantage - but not as big an advantage as a TALLER person would have (longer lever).

Hit a baseball with a wiffle bat

Now hit one with a standard bat

The 'lever' in the golf swing is BOTH the body, and the club, so at minimum a heavier person would have more mass in their 'lever'

Of course there is a relationship between how heavy and how fast. Assuming the same speed, more mass = more distance.