"I farmed a lot at first on one id and then just after switching ids it dropped one" is not a very convincing argument. Probability will go sometimes take a long time for a drop, who's to say that if you had gone skyly from the start, it wouldn't have taken just as long to get one? If you really want to try and guess at rates, then you need to farm several drops (5+) on a single id to get a more accurate average started. It takes a lot more work than most people are willing to put in to actually make any credible claims to rates (e.g. 2-3 years ago I would make personal estimates of Ultima Reaper rates between 1/300 - 1/400, based on averaging 10-15 drops' monster counts at a time, and repeated a few times). I think at this point in the event, any guessing at rates is just that, a random guess.
It's probably a good idea to put any and all rate speculation into a separate section with a disclaimer clearly stating that it is only guesses at this point, as there is clearly not enough to 'confirm' anything about rates; since the goal of this thread seems to be recording confirmed info about the event, separating the confirmed and unconfirmed aspects would be a nice thing.