So very sorry for your loss, and it sounds like you handled it all very thoughtfully.
We have a 13 year old hound at home, and I already have planned what we will, and won't, do when the time draws near. Our vet is fully aware, and will abide by our wishes. We want him to not be afraid, not be surgically invaded, and hopefully be able to wolf down his usual ten piece chicken nuggets (no sauce, too messy) on the way there.
Hugs to all....
Terri