If you really want to do this to some type of accuracy, one way is:
1-Get a very accurate balance.
a)Make shot of your refined gold by pouring in cold water.
b)Roll a bar or make a fine wire that will allow you to cut/add gold to your balance till you get the exactly desired weight.
3-Carefully weight each amount and place each of them in porcelain crucibles with borax.
4-Load about 12 crucibles in an electric furnace till they melt into a button, let them solidify and drop them in cold water.
They will not look like ingots however, but you can hammer them into any shape you want.
You could also attempt to manufacture or have someone make you molds of zirconia or sintered silica with the desired shape, but these will not be cheap.
"Platinum is the only metal fit for a King". King Louis XV of France