How long do you wait until you request a new winner?

The winner has 7 days to activate and mark it as received - you can submit the ticket after the 7 days passed.

Seven days. That's how long you have to wait.

I know that in theory they have 7 days, but if the person has been online since the win I don´t see why I should wait that long until I give the game to some of the other participants.

You have to because it's the rule, they have 7 days. Sometimes a winner can be on his phone or something and not be able to activate it right away :)

One week, and it's not an option, it's a rule.

You have to give them 7 days. I've got a few which have been online several time in the last week, but didn't activate it yet. Some of them have seen the key, so i'm not sure what happened to it.

But I've send them a message on their steamprofile or in one of their games they have given away here to activate and mark it as received. After that i'm down to 3 left that are unmarked..

I as gifter have 7 Days to provide the key.
So i give the Winner another 7 Days on Top.

So from the Point the GA ended to the Point i am starting to take steps to ask for a reroll i wait 14 Days.
But i do that only if it was not viewed / revealed.

I hate asking for a reroll, I wait the seven the days, if they haven't been online (Steamgifts) I send them a message about the fifth day, on the seventh I send a second message.
I then wait 3-7 more days if they still haven't activated the game, I ask for a reroll.

Being online doesn't mean he had a chance to activate key. Many people access Steam and SteamGifts using mobile platforms (smartphones, tablets etc), I do it myself a lot, Steam Mobile Client does not allow key activations. Keep in mind that last 2 days were weekend days - it's highly possible that someone will be travelling, will have no access to his PC with his Steam account, he will not have chance to activate the key despite constantly being online. So like people said before me - 7 days, doesn't matter whether the winner was online and how many times - it is still 7 days.

How can you tell if the key has been seen/revealed?

He finally marked it as received. Thanks for the replies.