I can't seem to adjust the toilet float ball perfectly: too high, and water runs out of the handle opening; too low, and the flapper gets caught on the float ball when the toilet is flushed. I've tried adjusting it repeatedly and there doesn't seem to be a "sweet spot" in the middle where neither problem occurs. Suggestions?

water runs out of the handle opening

Let talk about that part first. Water should never run out the handle hole, nor should it be able to do so, even if something malfunctions. To prevent that from ever happening, cut off the overflow pipe to a level 1 inch below the handle hole. Different people like different tools for doing that. I like to use a coping saw. Turn the blade sideways and cut off the top of the overflow pipe. Some people like to use a mini tubing cutter. Some people use a utility knife. A serrated kitchen knife would be better. No mater what you use, be sure and hold the overflow pipe steady as you cut because they can become brittle over time and break.

I don't know how the flapper could be getting caught on the float ball unless you mean that the chain gets caught on the float ball rod. You probably have a plastic chain that floats. Adjust the chain such that there is about 1/2" to 1" slack in the chain when the flapper is closed.

Adjust the water level to the water level line embossed in the rear of the tank or about 1" below the top of the overflow tube.

How argue adjusting the float ball? By bending the rod or with the screws? Back to you, Tom

The float ball's arm is plastic, so not bending! There's a way to loosen it and raise or lower it a notch at a time, but, as I said, it's either too high or too low. And, in response to the first answer, the flapper gets caught on the float ball itself when the toilet is flushed--the float ball goes to its lowest point, near the bottom of the tank, and the edge of the flapper hits it and gets stuck there. It can't close and the ball doesn't rise and the toilet just runs. I could try the suggestion to cut down the overflow tube, though, as at least that would prevent the water running out of the handle.

Turn off the water. Lossen the ballcock (fill valve) where is is attached to the tank, rotate the ballcock such that it does not interfere with the flapper. Re-tighten ballcock mounting nut.

If you cannot rotate the ballcock enough to clear the fill valve, replace it with a Fluidmaster fill valve, less than $10, and a better product.