You can figure out how many molds you can inject from your " favorite" injector, with a little plastic left over.
Then you can figure how much plastic you need to do say two "shoots" with a little left over. Inject a "set of molds" , demold , top off plastic temp. while clearing injector and inject a second set. Try that, go from there in multiple sets till the money runs out. But; as the gentleman said -- any production beyond what you can sell is of marginal value.