I've had a drop of 4 a couple of times and even 5 once but it's normally 2 or 3 from each more often than not. It is random as I have had all 4 drop only 1 each. I think the ability to craft enough talisman in time will mean setting your timer ever 3 hours or so or not missing many during the day. By the time I get enough p/jewels I'll likely be maxed on antidote. Break it down and make sure you're crafting 1 talisman every 2 days at most.