Weight choice has a lot to do with goals related to action, rate of rise/neutral pause, and stability at higher speeds as well
As with many things when building hard baits there is no set answer but instead it’s a matter of finding the correct combination factors to achieve the action you have in mind
Personally I have built enough baits I can make a really good guess or even design a bait where I plan to use no ballast at all. But float testing a lure is a really good way to figure out a good ballast weight. Or as I have mentioned in past threads tape or elastic band your ballast to your un finished but sealed lure and give it a test run. Try different ballast weights till you get what you are looking for