you can still buy 42#s and when you go to this size there is a lot more tuning involved due to the amount of fuel being dumped in per cycle.I would say if you run this size injector you will be pulling about 38% of duty cycle out for idle and cold starts.
You will still need to do one of two things no matter what size injector,if you run either size injector the tuning proccess is either analog IE:fmu calibration disk and adjusting your afpr or digital IE: chip at which you don't adj your timing manualy you set it at 10*base and the chip controls the fuel and timing curves.
I don't have a afpr or aftermarket fuel lines or rails.I can tell ya that you ran lean because you disconnected the inline fuel pump and your injector ran dry.I would invest in another fpr and set the idle pressure at 40psi with vacum connected and reconnect the inline and go from there.