Since your primary hunting will be yoters, here are some things to consider
.204
Pros - Flatter shooting, Much faster w/ better velocities. Smaller hole in the fur, if you sell pelts i.e bobcats.
Cons- Ammo is a bit more expensive and harder to aquire. Some consider the 30-40 grain bullets too small for handling coyotes and bobcats. But the .204 is an outstanding performer on small varmints such as prarie dogs and ground hogs.
.223
Pros - Wider variety of bullet selection, Ammo is plenitful and CHEAP!!!, Most likely a better performer on coyotes inside of 200 yards.
Cons - Velocity starts falling off at about 300 yards, Trajectory is not as flat as that of the .204.
My suggestion would be buy the .223 as it is located at your local dealer. I'm working on one myself right now for my "truck gun" but really and truthfully, any choice you make will serve you well...
sam