Here's a couple of things.
If you are right handed take the back steaks out from this direction (in pic). Make your first cut right along hard against the back bone and then start from the front (open the shoulder from the top where you start to get the max amount of backsteak). On the other side start from the hip/pin bone. If you are left handed do it the other way round.
This saves having to do gymnastics and it it comes off cleaner.
Attachment 230968
Attachment 230969
Next I take the HQ's off leaving the shoulders on to use as levers if I have to manoeuvre the carcass. Preferably I will hang the HQ in a tree or bush, or drape them over a scrub bush to skin and bone them. To let the meat cool I do this (bone them to the hip joint) and then just one cut drops it into a bag or my pack.:
Attachment 230970
Attachment 230971