I don't know - My little one is also 8 months and 20+ pounds, and I use the Maya Ring Sling - She faces forwards in the kangaroo pouch sort of way and I don't have any problems as of yet. The sling distributes weight across my back all right. Could be that I'm just used to her weight by now, but I love taking walks with her and seeing how excited she gets to be outside - she jumps in the pouch and all! Good luck to you though, soon they'll be walking!
11/2/12 at 5:00pm