We must be careful!
I've had my otherwise correct blueprints rejected from plan check 'causa my nasty habit of calling it THHN. They don't buy "You know what I mean".
Here's a couple of things that might help (or maybe not).
Rather than a timed panel, (I'm doing some guessing here), you might consider putting in a large box with listed multi pole lighting contactors rated per your individual branch circuits.
Use a timeclock and photocell to operate this.
A contactor can be used to operate certain security lights that stay on all night via the P/C.
Others can be turned on by P/C, and off by the time clock (just series the P/C and T/C, set the T/C earlier than dark).
You're not limited to 20 amp circuits here if these are HID fixtures, it can be up to a 50A, but you certainly CAN'T use a 100A circuit with #3 wire for anything other than a feeder to smaller C/Bs or fuses.