If you have some degree of knowledge about the target, and know they are somewhat security savvy (but also somehow only have a 4 digit pin protecting this account) then it might be wise to check the pins that would be considered more secure. Or, at least, to perform some data processing on the source data for this graph which culls stupid pins (and remember the ones you cull to add to the end of your brute force approach), and from there continue with the highest probability.