The saga continues...
I took 10 fresh rebuilt Botch injectors to a very reputable diesel injection shop today. None of them leaked, and every one of them was actually within specification as far as opening pressure is concerned, with some variability. So technically speaking all of them would pass a rudimentary examination.
However there was definitely a difference between them regarding the spray pattern, a difference that was clearly visible even to my untrained eye. Plus the technician pointed out how some of them had a certain amount of "delay", plus some of them had a better "chatter" to them. He explained how the lesser ones would be fine, but would most likely not last as long as the better ones. This is from a guy that does nothing but rebuild diesel injectors all day long for living. I found this to be quite interesting.
In conclusion, it seems that the batch that I first received are not necessarily indicative of all Bosch rebuilds being garbage. They generally seem to be adequate, yet not excellent. Perhaps my first batch was the product of some unusual screwup at the rebuild facility -- frustrating nonetheless.
Needless to say I'll be installing the five best ones tomorrow.
PS: PaulC: I'm not even sure if NEW injectors are available.