I've only done smaller online stakes. Both did the staking and was staked.
When I offered a piece of myself for staking, I usually did it for streaming reasons, to build an audience on my channel, and just to have some fun with it.
When I stake people, I look at these points:
1) Are they a good player? To me, they don't have to be a complete master of the game, but they have to be somewhat decent at least. You're not going to make a profit from bad players.
2) Are they trustworthy? Some sites allow you to stake players and the site will automatically divide winnings up between the stake percentage. If you don't go through a site that does that, then you have to trust the person, because it will be up to them to divide any potential winnings up. Make sure you get all the details on how winnings are divided up before any tournaments begin. That includes if the buy-ins are subtracted from winnings as well as potential taxes that need to be paid from it.
3) Is this person likeable? To me, I have to at least like the person. Someone who I think is a decent human being.
4) Is the stake amount within my
bankroll? Use the same rules that you use for your own bankroll. Is the amount you're staking an amount that you can afford to lose? If you stake more than you're willing to lose, and that player ends up not cashing, then you could end up harboring some disdain for someone who doesn't deserve it. Even the best players lose sometime.
Staking can be fun and exciting.