Whatever floats yer boat…
I refrigerate unused wet dog food, and microwave it to heat it up, too. Just 20 seconds, enough to take the chill off.
Sweetie’s weight on Wednesday was 45.6, so she has only gained a pound in the last two weeks. As I’ve said, the trouble is I’m feeding her high quality protein and fat, which is NOT the way to put on weight. I should be giving her Cheetos, potato chips, doughnuts, and sodas, right? Nah, she’s getting plenty of good nutrition. I’m giving her two satin fingers per day. I break them up and feed them to her by hand. If I put them in her bowl with the other food, she’ll ignore them. 
Time for me to make another batch.
She’s a late sleeper and a late night diner. Has been sleeping til noon or 1 pm. When she gets up, we go for our walk. Still pooping just fine! Not interested in food first thing. Afternoon, she shows interest, and then about 9 pm she will want 2-3 tubs of Natural Balance dog food. Her wish is my command, needless to say.
Not 100% sure the acupuncture is helping. It worked wonders with her comrade Buddy. I’ll keep it up. Can’t hurt, might help.
No first-hand experience, but I wonder whether something like one of these might help with Project Sweetie:
or
or
I bought this
which is similar to the first and third products you suggested. The first two ingredients in all of them are soybean oil and sugar. She doesn’t like it.
However, the second one, “Rebound Recuperation,” looks promising. Thanks.
Update on Sweetie, plus some metaphysical musings…
We’ve come to the end of the initial batch of 60 satin balls/fingers. I bought groceries to make another batch, but I’m rethinking. Sweetie was not that crazy about them. I’m exploring the idea of making baked meatballs with the basic satin balls ingredients instead. With the addition of some flavor enhancers.
Here comes the philosophical part: it occurred to me yesterday when I was running around in mental circles over her diet, that I’m exactly the same way about my own diet. 
(That’s the light bulb over my head.)
She is mirroring my own conflicts and ambivalence about food, grocery shopping, menus, when and how much to eat, etc. (Yes, a totally First World Problem, and I sometimes feel embarrassed about that. And humble.) I don’t want to eat the same thing every day-- why should she? And I sometimes make a big batch of something and then don’t want to eat a bite of it. I know exactly what I should eat, I love to cook, and I own a couple hundred cookbooks that I like to read like novels. And yet, as a woman in a household of one Old Lady and one Old Lady Dog, cooking for us is something I want to Get Right-- especially for her-- but I often don’t get it right.