Here is Timeknight’s last post.
And here is the thread with a link to the spreadsheet they used to calculate the scores.
Using it is pretty straightforward, if have a handy reference to the rooms for each faction’s delve (that info is annoyingly difficult to find). Just plug in the tallies for each type of room (common-legendary, plus a separate tally for guaranteed treasure rooms) and it spits out the expected multiplier and chest upgrade chance.
The main weakness this tool has is that it doesn’t factor in possible treasure rooms - only guaranteed ones. Do we even know the probability that these rooms can become treasure rooms? This factor would make the calculation a lot more complex, but even a simplified factor would improve accuracy a lot I think.