I'm at 7 strength, and over heavy load but not 2x over it. I'll be at medium load if I can drop the backpack easily. I'm pretty sure there is nothing special about dropping a backpack. (masterwork but nothing like harnesses)
...I was trying to figure out why Mythweaver had my load a lot higher than it should have been, it was double counting all my equipped items because I listed the weight in the top section and the inventory part, so I removed the weight listing from the inventory section. 40 lbs worth of armor/weapon/items on belt.

I was going to take the shocking grasp wand, but didn't actually write it down and don't think I explicitly got it from Adalbert at any point.