How to negotiate a Sacrifice (necro spell)

[Polixa]

Not sure how the mechanics work.

1. Who holds the emerald, the necro or the victim?
2. Does the emerald need to be on the cursor or just in a bag?
3. Which player gets the essence emerald on completion of the spell.

I'm guessing #1 and #3 = the necro, not the victim, but just checking.

Per the wiki the EEs are offered for sale/purchase at around 250pp. If I am a willing victim would I try to find a necro willing to pay me 250pp each time they sac me?

Alternatively would I pay a necro for his time and I get the EEs and try to sell them in the tunnel? If so, what would a going rate for a necro's time look like?

If we came to an arrangement where the necro and the victim each take a share of the EEs what kind of split would we be looking at? Necro takes 1 in 10? 3/10? 5/10?

I appreciate you can negotiate anything you like for this, but I wouldn't know where a reasonable starting point for negotiation should be.

Last question, do the EEs stack to 20? Would players typically do 20+ at a time?