My son is 3 and has outgrown the top slots of the harness on his Sceneras. He rides in a Marathon most of the time but the Sceneras are installed as extra seats in all the grandparents cars. My question is what seats to buy next? Albee has Regents on sale for $159 or Target has Nautilus seats for $135. He is average torsoed and not too heavy, he weighs about 33lbs right now and I am unsure of his height. His shoulder height is just a smidge above the top slot of the Scenera if anyone knows what that is. So, Regent or Nautilus or is there a better seat I could buy? Thanks!