Since I have a theory of Correlated decision making, let's use it! :-)

Let's look longer at the Nick Bostrom solution. How much contribution is there towards "feeling I will have won the lottery ten seconds from now" from "feeling I have currently won the lottery"? By the rules of this set-up, each of the happy copies contributes one trillionth towards that result.

(quick and dirty argument to convince you of that: replace the current rules by one saying "we will take the average feeling of victory across the trillion copies"; since all the feelings are exactly correlated, this rule gives the same ultimate result, while making it clear that each copy contributes one trillionth of the final result).

Thus Nick's position is, I believe, correct.

As for dealing with the fourth horn, I've already written on how to do that: here you have partially correlated experiences contributing to future feelings of victory, which you should split into correlated and anti-correlated parts. Since the divergence is low, the anti-correlated parts are of low probability, and the solution is approxiamtely the same as before.