That I haven't checked into, since I don't keep finches. I know it's great for both cockatiels and budgies. I do know that a Gouldian breeder (I was looking into getting Gouldians) was recommending the brand for them. They don't make a pellet just for finches like Lafeber's does, though...
Harrison's has three sizes, super fine, fine, and coarse. I use fine for the tiels, but super fine might work well for your budgies. As a bonus, super fine is also the size used for finches, so you might be able to get all your birds on them.
Cricket was a bit tricky (my cockatiel) but he's fully on Harrison's pellets now. The natural coloring helps, I think, and he also eat Roudybush and Zupreem naturals, but both of my cockatiels prefer the Harrison's so that's what I use.
I used the method of mixing in with the seeds and just...