Cat won't eat redux

[+7Paper]

I adopted my 12 yo male cat about 6 weeks ago from the shelter. He had had extensive dental work but did have vomiting and diarrhea issues. At first, he had a healthy appetite but would vomit after eating. Things have been better since I switched to small amounts of food. After a vet checkup ( clean bill of health) he was traumatized and didn't eat for days.this is when I sought the excellent advice on this forum. and, he started eating again.
Now, a new problem: he has become EXTREMELY finicky. There is one thing that he will eat consistently -- Temptations cat treats in the red bag. I can't find any one thing that he likes on a consistent basis. If he eats it at breakfast, then he doesn't want another serving when it's presented. From one day to the next, from one meal to the next I can't figure out what he will eat.
He's always hungry, always underfoot, always yammering but will only eat intermittently. I'm old, have had close to 40 cats but have never had this problem. Please help.

[Kay]

what have you tried him with? wet and/or dry?

not everyone would agree with me, but I do think it is easier to deal with a finicky cat with a good quality, grain-free dry food, because it can be left down all day and night if necessary - and it's easy to weigh it out so you know if he is eating a full day's amount, or how much he is leaving

[+7Paper]

I've tried both. four different kinds of dry. When he first came, he ate some of one kind of dry but none since. I did measure so i could see if he was eating and he wasn't.
Many different varieties of wet. He does seem to favor beef or duck, not any kind of fish, but still this wildly fluctuates as to whether he will eat what I put out. There are some days that I think he might eat a tablespoon of food.
coat looks good and he has lots of energy. I'm flummoxed.

[fjm]

Will he eat cooked meat - chicken, beef, etc? And does he go outside? If he is maintaining his weight and condition it sounds as if he must be getting sufficient nutrition somehow...

[+7Paper]

No to cooked chicken. I haven't tried beef but will give it a try. And, no, he doesn't go outside. He was rescued approx sept 1st. they said he was very thin so I don't know how long he was a stray but he doesn't want anything to do with outside.
Maybe he is maintaining since he looks good. But, he yammers for food a lot which he won't eat and is constantly underfoot. Right now he is hiding under the bed because my husband stepped on his tail today. I stepped on him last week.