The chart above can be subjective and there are other variables, such as fuel pump condition, HW, altitude, humidity, etc. So make sure you get a bigger injector than what your planning to run ET wise, it will make things a little easier and you won't have to have "perfect" conditions to get enough fuel if your running right at the edge of an injectors capability.
The 50# and 60/65# injectors are the same cost. I just bought a new set to replace my 40#s, which should have been good well down into the 11's, but have only went low 12's with them and they were running at 108% DC with O2s in the 780's with a new Walbro pump.
I went with the 60/65# because of the better idle quality suposedly since they have 3 nozzles on each injector for a better spray pattern and are supposed to be as linear or more than the 50s. Some vendors call them 65# while others call then 60#..all has to do with the DC they were flowed at.
