B.W.
Aftermarket products are not safe to use in a car seat , and a toddler should still be in a 5pt harness car seat. A 5pt harness convertible should have adequate recline so a childs head doesn't bob. If you need help installing your seat properly, so your childs head doesn't bob, please find a CPST in your area through www.safekids.org
If you have a convertible car seat and your child is under 35lbs and has more than 1" of shell above his head, turn him back rear facing. The AAP recommends children remain rear facing as long as possible, until the rear facing car seat is outgrown. And in the rear facing position, the seat can be reclined much more, and your son will sleep alot easier. Please google EXTENDED REAR FACING for more information.