I'm starting to appreciate the world-without-prams and ready to give up on hoisting the car seat onto the unwieldy wheels if I can get away with it. DS, at 7mo is growing out of his Baby Bjorn. The world of slings seems rather daunting and varied, and I'm slightly terrified by the idea of my PFB's only support being knots tied by me (dizzy by name, and by nature). Lots of sling advice seems to be based on carrying tiny newborns curled up like prawns. What kind of sling would you recommend for an older baby, 18lb+, without killing one's back?