LDD what about feeding them both at the same time? So Nimbus gets his 1/4 cup and Grue gets her 1/2 cup, or alternating dry/tinned etc at the same time? IF Nimbus eats too quick for Grue maybe get Nimbus one of the cat Kongs? That way he has to work for his food. I also like the look of the cat-it feeders, it's like a maze and they have to get the food out.
I might try that. The problem with feeding them at the same time is Nimbus sits his butt down and eats with actual dedication and Grue takes three bites and runs off to play a game or investigate something and expects an even share of food when she comes back.
So far I've found it has to be something really great (like boiled chicken) for Grue to actually determinedly eat it. So I might start cooking for them again, and giving him a bit of chicken and her a bigger piece. It's just she's such an idiot that she goes from not caring at ALL about kibble to sitting there growling and carrying on about chicken and even Nimbus just looks puzzled about what she's so mad about.