Often walk to school with ds and dd1 and dd2. dd2 is 4 months old and I like to change around how we travel. I travel through town but up hills too so find pushchair a bit tiring. I use baby bjorn on front but am interested in ring slings or hippychick. Are any of these any good? I find everything pulls on my back. How do you ensure baby does not fall off hippychick? (Assume it is for slightly older babies but even so!!) Any advice would be helpful! Has anyone ever made a ring sling? Thanks alot!!