[edit] Unless you can do a one pass portage, or have at least 3 people in your group, you have to drop your food and leave it at some point, or do people hang there food at each portage. Drop your food halfway maybe, to try and trick a smart old bear poaching the trail heads,   [/edit]

I worry about that traveling solo, so to ease my mind I came up with my own personal bear alarm. I keep it in my tent at night just in case I get a night visitor and the usual shouting doesn't scare them away?
It's a personal security alarm the size of a deck of cards. Runs on 9v battery. When the cord/pin is pulled it sets off a high decibel alarm similar to a home fire alarm.
On portages, I tie the cord off to tree/branch and the alarm stays in zipped side pocket of food pack. Bear grabs/disturbs pack, alarm goes off.
I can't imagine a bear or any wild critter being able to take that sound? Of course if it were a smart OLD bear, they might be deaf ;D

I hear what you say about the molded handles. Maybe the difference wouldn't be enough.