FYI 407c evaporator glide is generally said to be 8 degrees F.
The bubble and dew are 11 degrees apart at a normal evaporator pressure. Flash loss will never allow the bubble temperature to be reached in an evaporator.
Average evaporator temperature will be four degrees less than the dew.
Im not sure how many orings are in the system but as mentioned in a post above, they will need to be changed.
Also, I normally start with 90 percent r-22 nameplate charge and adjust as needed.