I never thought about using a timed feeder,I'm curious how it would
work with 2 cats?

How much is that 1/4 in grams and how much does that translate into
kilocalories or kcals or caloriess (technically not correct but is the
common usage).

You may still be feeding fattie too much or there is a problem, like a
thyroid problem or something?

What prescription diet are you feeding, Science Diet r/d? or something
like that? I forget it's initials.

1/2 cup sounds right but not losing weight. Do you have a baby balance
to weight in grams or extremely accurately? I am thinking of a postal
balance but that is net setup as well as a baby balance which can cost
a little over $100 to buy.

I had this problem with my cat but after I started computing each gram
of food into the "calories" that it had, the cat started losing weight.
It's quite easy to feed more. Like snacks or something, even an extra
10 or 20 calories can screw things up.  But at the gram level, one
knows how much energy the cat is getting.

Also, I am thinking of using wet food again. That seems to help health.
I include some Science Diet Oral Care to clean the teeth if using wet
food. But its gets tricky since now I have to deduct the calories from
the wet food.

Generally, my cat is on 160 calories or kcals per day. How many
calories are you feeding your cat?