You're right about weight and Archimedes, except that the hull is (reasonably) symmetric along the centerline, but the weight is not necessaeirly so. So, depending on how it is loaded, the boat may list to port or starboard.
And underway, prop torque, depending on direction of rotation, will also attempt to induce list relative to the static floating position.
I *think* the question of where the helm should be has to do with the driver's weight (as well as a bunch of weight from wiring, cables, steering, etc.) offsetting prop torque. I *think.* Which may sound a bit silly, but I bet most of these boats do spend most of their time with more human weight on the driver's side. (With only one person aboard, or a big dude behind the wheel and a lady in the shotgun seat.)
And if that weight and the prop torque are additive, rather than counter to one another, on the little 7' beam, it's probably not what you want.
I *think* that's what was meant earlier by "adverse-handling issues."
"I don't have time to get into it, but he went through a lot." -Pulp Fiction