Bailey is 3 years and 7 lbs - I feed her twice a day (always have). I feed her one overflowing tablespoon (not measuring spoon but everyday tablespoon - the larger of the dinner spoons) of homemade raw (hamburger, cottage cheese, rice, etc). - twice a day.
A 1/4 cup of kibble plus 3-4 spoonfuls of tripe seems like a lot to me.
We battle weight problems too - it is very difficult to feed Bailey what seems like so little - but believe me, its more than plenty - and we have to monitor the snacks too. I jokingly call her my 5 lb yorkie in a 7 lb body
Good luck! There are so many finicky eaters - its kinda good to hear about a hefty eater!