Thanks for the input. As seen in the preparation thread
it has been a ready-made curing salt mixture with quite some ingredients in unspecified quantities (and it's the only brand available here), but the bottom line is, the manufacturer's instructions are not working for a single piece of meat. I don't know if the ratio of curing salt per pound is supposed to change on higher quantities of meat, but following the instructions I used way too little. The other problem has been the rub resulting in a flavor profile that was quite off. So if there is another time I try pastrami I'll try wet curing and a simpler rub. The rest of the procedure should not cause any troubles.