I’ve got a light, and suffer depression as well as SAD specifically.
I also am naturally a night-owl.
I’m personally careful to not use my light after about 8am, partly because that’s when I get up, and partly because I live in horror that I’ll push my natural sleep schedule any later.
I also don’t run the light more than 45 minutes before I get up - I’m not what could even charitably be called awake, but I keep the snooze on the alarm running for that 45 minutes, and I am aware that the light is on.
I got it for the first time this fall, and it is AMAZING! I am into February without wanting to slit my wrists, and without being on meds.
From what I know, as long as you aren’t truly desperately depressed, it’s better to run it in the morning only, because the light in the evening throws you off and triggers your brain to want to be awake - and since most of us with depression don’t need to lie awake at night unable to fall asleep…
If you’ve been using it to wake up for a while, you’re probably used to the amount of light that you’re getting, and maybe you could use it later in the morning while you’re at your desk?
The restrictions on the intensity and peripheral location are the same for SAD use as for mucking up your circadian rhythms - it’s less a set of precautions for specific use for circadian needs and more a set of precautions to make sure you don’t burn your eyes out on the blue spectrum light it gives off.