I'm in the market for a new high back booster. I have a Graco Nautilus that needs to be replaced because it was in the car during a car accident. My mom has one too, but doesn't like to transfer it between cars because it is bulky and heavy. She has fibromyalgia and can't lift much. When in other cars, she just puts DD in a low-back booster. I don't like it, so we reached a compromise. I would find a high back booster that is lighter, and I would take her Nautilus. But I need advice on what would be best. Any ideas?
ETA: DD is 7 years old, 42.5 inches and 47.4 pounds.