What I do is to get the trim near perfect and then make those small corrections with the stick. Works out pretty well. It wont trim perfectly level, and from what i have seen in vids, that's how it's done IRL.
It takes time to learn the F-5, but after a while it becomes second nature. Reference your surroundings down low as well as your VVI. At altitude you need to more frequently monitor your VVI and altimeter for reference.