Some of the feedback from our early BagPack customers was that we should give more guidance on which bags work best. This was the reason we introduced our newest Amazon product, the BagPack for Hands Free Groceries with Bags.
What you’re looking for is a durable bag with long, flexible handles. The handles can’t be just big enough for a hand. They need to give enough room to get your arm through. You can test this easily with your bags when they’re empty. Just lift one up by the handle and try to pull it up to your shoulder.