My almost 6 year old (51 lbs and around 48 inches) rides harnessed in a Britax Frontier CT. Like many, I chose the seat intending to keep him harnessed (he is a wiggle worm) for years to come. Enter Consumer Reports with the news that the harness may fail at his weight. Should I transition to belt positioning booster mode? It just seems really scary to me not to have him in a harnessed seat! Is it worth buying a Chicco MyFit or Evenflo Evolve to stay harnessed to 65 lbs? We do have a younger child who will use the seats again in the future. Thanks!