One can only hope that JB used good engineering discipline that produced a laboratory notebook. Trial and error is old school - like Edison. Present day engineering uses Design of Experments. To get a rough idea about how it is done look here: https://www.moresteam.com/toolbox/design-of-experiments.cfm? or here: http://thequalityportal.com/q_know02.htm . Design of Experments minimizes time, number of experments, and cost.