Yeah, you're fine doing it that way. And you would probably save money if you bought a balljoint press. They fit, trust me. I've done literally hundreds.
And BJ presses can be rented for free at most auto parts stores.
I have heard of this method for years. I have had zero luck with it. I believe that is because I throw ball like a left-handed 4 year old girl and I swing a hammer even worse.
Dead blow ball peen my friend.