Yup, them's hills awright.
Wish I had some of them in my back yard.
Your angle of shooting looks fine to me.
Although it wouldn't take a huge mistake to hit that house.
But, if the folks who live there don't mind, no one else should, either.
And the group you shot is not nearly as spread out as it looks in the first set of pictures.
Those were taken more square to the corner of the shed than the bullet paths were.
As for adjusting for a disability, have you tried the reverse Weaver grip for handguns?
The support arm is almost straight, like you would hold a long gun, and the primary grip arm is bent.
Bass ackwards from the traditional Weaver.
It feels mighty weird at first.
But it definitely helps creaky, older folks hold steadier and shoot better.
As serious competitors, who are approaching middle age, have discovered.
Do a search on youtube to see what it looks like.
It might just help.