A bigger wheel is better, Pro Stock runs a 1" + diameter wheel for a reason. Trying to save weight on the push rod side will be a fruitless exercise, over the valve is a different story. Stiffness and rigidity wins, hence why we see lifters around 1" in diameter with 1/2" + diameter push rods.
That said, your camshaft profile will have been designed with a wheel diameter in mind, find out what that is.