If you have a bad back, facing outwards and hip carry both will put more strain on your back. Ideally, a two shouldered front or back carry will provide your back with the most support, as the weight is supported evenly. A facing outwards carry will pull forwards on your shoulders, and a hip carry puts more weight on one shoulder and throws the spine and hip out of alignment.

However, there is a really good hip carrier designed for toddlers - the Scootababy. It has a similar structured waist to the Ergo, and a very comfortable Windpro shoulder. My bub is 17 months, extremely tall and about 11.5 - 12kg, and I have a bad back and shoulders. I have carried him for hours at a time without discomfort, but I find a good woven wrap or my wrap converted Mei Tai to be the most supportive for extended wearing.

An Ergo may suit you (they do not suit all people, I have narrow shoulders and never found the Ergo comfortable). If you are looking into Mei Tais, different makes are more suitable for older babies (eg: Kozy) - they use more supportive fabrics, or padded or structured waistbands and have taller bodies, whereas some are more suited for smaller babies.

If your bub likes looking out, perhaps he will like a high back carry in a mei tai or wrap, where he can see over your shoulder.


ETA: I wouldn't recommend a pouch - they are not the most supportive for people with bad backs.