I've been watching very closely for a while and have been using a spreadsheet to monitor... What I am about to tell you is NOT 100% as there are breakout films and higher delist ratios resulting from WOM, A+ cinema scores, etc... But for a usual film, I have found that I am getting pretty close (1-2 mil) of delist, very early after release. So I watch movies bounce all over after initial release, but my methods allow me to hold my positions and brave the storms/other player uncertainty. I also know when to drop the movie and when it might be profitable to buy in again.
This does not apply to movies like 12SLV that have had multiple expanded releases. It applies to films that either release wide, or have 1 expansion from ltd to wide. I hope it helps newer players think about how they want to play MSTs. When my chart is complete, I may post a full report for you, as I sometimes do with all my experiments - but for now, here's what I do. Again, I hope it helps in some way. DISCLAIMER: You know there will always be outliers. Watch out for them and play accordingly.
So, a movie goes wide and makes a whopping 30 mil OW. Now what? Until the 2nd weekend estimates are posted, there is little a person can do but play a ratio or "the bounce" or follow the players, etc... Horror genre, for example, has a historic adjust ratio of about 2.0. That means if a movie opens at 30, weekend adjusts for 81 (2.7*30), it would be a likely short to a 60 delist after 4 weeks. Animated films/kids movies sometimes push a 3.0 (if they are good - we'll see about Frozen), and basic action flicks are showing about a 2.5 (2.2 for lesser action films and 2.6+ for decent ones). Poopy films just die off and are easily identifiable. Ratios don't apply to them. If it sucks, ignore ratio discussions altogether.
Moving on...the 2nd weekend comes along and we learn it's new total is 50mil! What I do is find the difference between 2nd wknd and OW, and then add it to 2nd Wknd again. CUME - OW + CUME: 50-30=20+50=70. I would now expect the delist to be around 70.
After the third weekend, we find a cume of 63. I simply take the WEEKEND earning ONLY, and add it to the total, post 3rd WE cume. I don't care what it made during the week except to know what the new total is. For example, it made 5 mil during the week and another 8 mil on the weekend (13 mil for the week). So its new cume is 63 and its weekend only total was 8. 63+8=71. That's my new delist estimate. (Note that it is already, but only, 1 mil out from original estimates).
For full delist, monitor sites for 4th WE estimates and you are done. For movies with one expansion from limited to wide, ignore previous grosses on 1st and 2nd post OW estimate. (i.e.) movie makes 1.5 mil LTD and on OW wide, it makes 25 mil. 1st estimate after OW wide: 25*ratio=x + LTD=estimated delist. Second weekend = (CUME - 1.5 - OW wide) + CUME. The remaining estimates are unaffected by LTD. CUME + weekend totals = new estimate.
Summary:
Plan before OW = good luck
Plan after OW, before 2nd WE = ratio or play the player/follow the masses (slightly different for LTD to wide expansion movies, see above)
Plan after 2nd WE, before 3rd WE = 2nd WE total - OW + 2nd WE total (slightly different for LTD to wide expansion movies, see above)
Plan after 3rd WE, before 4th WE = 3rd WE total + 3rd WE gross (no change for LTD to wide expansion movies)
Plan as 4th WE rolls out to delist = Final changes based on estimates as they come out during the 4th WE, delist on Monday. (No change for LTD to wide expansion movies)
I hope this makes sense to you. I would be interested in any other players' methods they might be willing to share. Good Luck.