Another idea is this .....
All four heatsinks (ex plan:two separate panels ) to be one panel ....
One only pot will adjust the current to all the CXAs (one pot for four drivers ) and the duty cycle
of the pwm controlled fans ...
One DPTP switch will handle the alteration between veg/flowering mode ...
A single pwm fan controlling pcb/circuit is needed ..
Only one pot ..And only one Amperemeter
And only one ON/OFF switch ..
That is the most economical design with least control ...
The most expensive would had 4 ON/OFF switches , for each driver
One on/off switch for the fan's 12-15 VDC psu
4x double 100K pots
4x PWM fan controlling circuits
2x spectrum change switches
4x amperemeters ..
And a really huge box to place all these inside /upon ....
I think i like the idea of one single panel ....
At max of 1950 mA ,the CXA 3070 ,has a VF of ~38.5 Volts ..
Thus 1.95 * 38.5 x 4 = 300,3 Watts ...
The 4x CXAs of the fixture will dissipate ~300 Watts at the max setting of the fixture ..
With an average of 35% efficiency , ~ 195 of those Watts are turned into heat ....
So ..
Cooling ...
Starting point : Dissipate 200Watts of heat ...
Passive Cooling Components :
Four 200x160x40mm heatsinks ,each with 16 fins .Rth = ~0.5 C/W ( aver.)
Total mass of ~8 kgs ( ~17.6 lbs ) of soft aluminium alloy ( AA 1060/1061 A )
Active components:
Four 120 mm fans 12-15 V ,
still under question of which type and speed/airflow/power/electrical characteristics ...