I voted for deal with percentage held for first place but I think it is situation specific.

I have only been in a deal situation at dusk til dawn once which was the Friday night sky poker tour warm up event.
We got down to the final 4 and two of the players were playing in the sky event the next day do as it was very late, one of them proposed a deal. After a chip count, I was in 4th place which would have paid about £650 but the deal was to make me £1050 and after a £50 tip to the dealers meant I was walking away with a grand sp accepted the offer.

If I had been chip leader, I may have decided to decline the offer with a chance to take away more than double this amount armed with the knowledge that the 2 players entering the sky event the next day just wanted to goto bed.