Setting of Hand expansion valve

Blast freezer with 20 evaporator coils liquid overfeed and hand expansion valve to each coil.
I'm looking for best way to set the hand expansion valve?
I know coil/freezer mfr says a 3:1 or 4:1 overfeed. First evaporator coil sees much warmer product so more vaporization there than later coils after the latent zones so these valves are open more that at exit of freezer. Any good tried n true methods out there for setting the hand expansion valve? I read Industrial Refrigeration Handbook by Stoecker and the chart on Circulation ratio but it doesn't explain how to get the overfeed setting for each coil. With the multiple coils how do I know what ratio each coil is getting, 1:1, 2:1, 3:1. If hand expansion was fully opened they could be grossly overfed especially the last coils.

I could go on and on with this. The initial settings can be calculated from the Manufacturers literature, if you know exactly which valves they are.
But this link tells it best.
http://www.permacold.com/Fall05.pdf

Big Thanks. I had lost my PermaCold newsletter and miss Ward and Dave's brain to pick.

Adjust the coils farthest away from the pumps or at the highest point first. Then work your way back to the pumps as the last steps.

It is not only the overfeed rate, but the pressure the pumps develop also.

One thing that can make things even more difficult is if you have a pump not large enough to maintain pressure, or with large line losses.
When this happens every valve adjustment affects all the others.
Lets face it. Most of the time we make a educated guess on the settings.
A plant with a competent operator is always better off than those who contract out all their work. No manager wants to pay the bill for a service person to tweak valves and check temperatures when he sees nothing changing.

Sometimes, coil manufacturer can give the pressure required for proper liquid supply. This is pressure between expansion valve and orifices. In real life you see this pressure on defrost BPR pressure gauge(bottom feed coils). Compare this pressure with suction pressure and you have liquid supply pressure.

If the coils are manufactured the same way as new ones, the minimum inlet pressure to the hand expansion valves is approximately; evaporating pressure + 5 psig + the pressure loss of the hand expansion valve.

I agree that inlet pressure to the orifices should be in the range of 5psig + suction pressure. So, if suction pressure is 0psig, we can adjust hand expansion valve to get 5psig inlet pressure to the orifices.