Okay, so which way to read doesn't matter. I haven't got the hardware fully setup, so the 512 value is a placeholder until I find the real world value.
The Mega I'm using doesn't have 32 or more spare pins necessary, so I went with external ADCs instead.
It's a pretty big project: 32 or more LDRs, 22 outputs for relays and 22 servos driven by PCA9685 boards all on one Mega. All LDRs data are sent to and external computer program via serial. The computer program sends the outputs to the mega for the relays and servos. Not sure if Structs and Classes would complicate the data transfer to the external computer(actually a Raspberry Pi). I can add the full program if you would like to see it.
Current cycle time of project is approx. 65ms. to read inputs and send outputs to all devices in one program scan.
Mandy