When does Zannok restock?Follow

I'm a leatherworker and have been trying the pattern for Heavy Scorpid Bracers from Zannok Hidepiercer in Silithus for days now, but no luck. He's always sold out when I get there. I even tried to check every hour on the hour one morning, but still no luck, so I gave up for the rest of the day.

He only has one pattern to sell per day, so it would be really useful to know when he restocks. He also sells the pattern for the Heavy Scorpid Helm, but do these two patterns restock at the same time?

Any ideas, people?

PS: Could you please give times in server time, to avoid confusion.