Split lines are an issue only if the restriction built into each run is not the same. This is the reason for the previous question on the amount of 3/16" at each location. Since you are using one pump for two different run variables (lift, length, hardware), you must take these variables into account and build each run to have the same back pressure.
Another issue would be if your circulation system is ineffecient and incapable of maintaining temperature the length of the run. What is your glycol bath temperature?
One last consideration is your pressure to the vessels. Is this pressure assuring that no gas is breaking out of the beer as well as none is being imparted into the beer prior to the beer hitting the pumps?
Scott Zuhse, Instructor
Micro Matic Dispense Institute