I run 24/7 in veg.
Please take no offence as I'm not challenging anyone's personal preference on lighting.. I'm challenging the thought process behind it...
Plants aren't people. They don't need sleep. Their systems are designed to function while it can (during light hours)... the reason it slows down at night isn't because it needs the rest.. it's because the sun isn't there. It photosynthesis - and it relies on light to function. If my mothers needed sleep.. they wouldn't be alive according to the rational behind the "rest"period and that I would be tired if I was up for 6 weeks has nothing to do with it... I get tired if I'm up for 6 hours
my plants have been up for over a year, and every 2 weeks I cut the shit out of her to make all my clones, and every week she comes back full and ready.
It's the same type of thinking that lumens have anything to do with plants. lumens are for humans.
I say it's a personal preference and what you want from your plants - 18/6 is pretty standard for veg, and is likely the schedule you find most growers go by, I've read that 20/4 is the best only from an energy consumption stand point from the way I understand it.. and I go 24 hours a day on and get the results I want from my plants.. just my 2 cents, and that won't get you much but a different opinion these days..cheers.