Next seat after RA for small four year old

[MariaMP]

My son is 38 1/2 inches and 35 pounds. He has grown less than an inch in one year. What are the chances that he will reach the weight limit for his Britax RA before the height? If that happens, can he stay in the RA? Without a winter coat, his straps are from the middle slot. If he can't stay in the RA, what is the best seat out there for a situation such as this? He loves his RA and sleeps easily in it and he likes being higher up than in the Next Step DX in Dad's car. Any input is welcome. Thank You.

[MarieMW]

This is the seat I bought after the roundabout. My daughter loved it. I bought a Cosco/Edie Bauer one between the RA and the KK, and it was uncomrfortable and broke after 6 months. I guarantee your child will love it!