For the coins I vary the thickness to get a variety of weights. When I want to add a precise amount to the pot, I can just pile the them on a scale and add or subtract a few until I hit the target weight. I used to pre weigh and mark the individual coins but find it easier to just grab a random handful and eyeball adding or removing thick or thin.
That floats my boat, but I'm not saying it's wrong to toss a coin or two into the pot until it casts right and call it good.