I have 32 HEX16A2 boards from Technobit.
What is the best and safest way to power them? I had planned that a PSU CX750 from Corsair would power 10 in my opinion, but it is clearly insufficient..

Based on CX750 spec, 12 V rail can supply 62 A. One HEX16A2 use about 9 A.
So 1 unit PSU only able to supply 6 board of HEX16A2.
And please noted that one modular molex power cable can only sustain 1 hex16A2.
7 if they run at 92W each. Put I'm pushing it atm. lol