Okay, so… I’m looking to start 5A, so I’m digging around for other ideas aside from the Duncan counterweight set, I’d rather just get a bouncy ball from a gumball machine and drill a hole in general. I know that nearly anything that can be palmed in your hand could be placed as a counterweight, but just asking out for ideas and such. Do normal sized dice work in place? Not entirely sure on the weight needed/recommended, or if it’s mostly just preference (which I’m mostly sure it is). So yeah, shout out some ideas for home made counterweights. 
Those 25 cent bouncy bals are good for starting CWs. I also went to a craft store and picked up some clay, hardened it in the oven, an that worked real well. Took some trial and error though.
Honestly though, if you want to get into serious 5A, Duncan CWs are the way to go.
Counter weight sizes and weights are exactly what you said. Preference.
I like small light counterweights, some people like heavy ones.
As a suggestion, if you use a bouncy ball, get the plastic thing in a pen that hold the ink and cut a piece thats about as long as the diameter of the ball, and place it in the ball hole (glue if you need to). Or use a tube similar in size to that if the pen one is too small. Otherwise, the string will slowly rip through the ball.
As much as I hate to admit it with all this silly patent crap, I love the Duncan Dice. They are just perfect… Tho I learned on a die my brother stole from a casino.
I plan on getting some Duncan weights later on next month, just looking to get a decent homemade one before then so I can get a little head start on it. Thanks for the tips. 