Well, I kinda thought your problem with CX is they don't lay.
For certain, you're not breeding if you're not getting eggs. Ducks get nice and fat in about 9-12 weeks. And they're really easy to keep, very winter hardy. But they're not the meat bird of choice because you're not getting eggs when...
I haven't, but I'm going to give it a shot. I have a Buff Cornish rooster and some White Leghorn hens, and when I can set up some grow out pens, the plan is to raise them out, keep records and do the math. Someone mentioned that their 3 heavy hens would pump out 14 eggs a week - 3 WL will do 21...
Same old answer; not really.
Your best meat bird is pretty much always going to be a crossbred. I've had good results with a fast-maturing White Leghorn or California White rooster over "dual purpose" hens, but you lose that fast growth and breastiness in the next generation - F2s are always...