Ok, I'm starting to get it.
You start by approving some nodes (aka delegates, you give them thumbs up). This is your "approved subset"
(Is this giving them stake? Probably not, TBD...)Then (on the voting tab), you can transfer your entire stake to these nodes (chose "all" & click "vote"). This also creates a dummy transaction to your self (for your entire balance, for which you pay 0.5 BTS fee). It appears every member of the "approved subset" gets 100% of your stake. The total stake transferred in the process is [number of approved nodes] x [your account balance]
It may be possible to transfer less than 100% of the stake, using technique described in
http://wiki.bitshares.org/index.php/DPOS/ApprovalVoting .
What is the use case for this? IMHO "delegate" is at first confusing - in NXT it's used as a verb "i delegate my stake". In BTS it's a noun for a particular kind of node. Which may lead to sentences like this "Your entire stake is delegated to all approved delegates". They should have called them Representatives or Electives , etc
So now onto the main question. I need delegates that (upon receiving my stake), will reward me with part of their profits.