I don't think anyone's thoughts are pertinent but yours, Rob. This is
your animal, you have some kind of emotions toward it, you know your
psychological condition and you know all the factors of the choices.
My beloved Dax died easy with the vet's single injection into his
foreleg. I had my right arm around his neck and was petting him with
my left hand and I know for a fact that he died quickly and without
trauma or pain.
Years ago, at Chris's urging, I shot a cat to death. I will never do
that again. Never. It was traumatic for the killer and the animal. A
needle of magic killer potion is gentle and painless and there are no
chances for pain or mistakes.