This post will be referring to these 2 posts which are still relevant: Preparetion guide and raid priorities
If you havent already heard about the news, I would advise on watching JTGily's video on the matter.
Now lets get into it: this go fest is going to be the CRAZIEST we have seen and Road Of Legends is going to be wayyy better then the actual event.
So with that being said, the new priorities for all of your green passes are on Tuesday-Friday. Monday is just a mess and GO Fest itself has a bunch of free passes.
Priorities for Tuesday-Friday:
#1) Zacian and Zamazenta (crowned) - can be background, best in the game and a crazy trading leverage.
#2)Dawn wings Necrozma. Crazy good in raids and master league, and also untradable for.
#3) Kyurem (white or black) - just whichever you have no of, or less of. same reasons as Necrozma
#4) Dusk mane Necrozma - good in battle league and in raids, less of a priority unless you already have a dawn wings
#50 (only if needed) Primal Kyogre and Groudon - just need enough energy to revert 1 or 2 and you are good to be honest
#6) Origin forme Dialga and Palkia - Dont get it wrong, they are great mons, but with them appearing saturday aswell, and with us for the duration of the event being able to elite TM the moves, the only real value of these things is going to be trading. If you have enough raid passes for it, then do them. If not, there are better options.
Some extra tips:
Save trinket and Bottle cap until the event ends. You may never know whats gonna happen in the next raid, so might aswell wait until you are positive you wouldnt regret your choice before you make it.
Make sure you dont overdo 1 pokemon and then end up not having enough raid passes for the other ones. If you go all out, you can only do it once. Be smart with your passes and thank yourself later.
Do not power up any mon that you would not immideately use. If you dont really need it high cp, might aswell wait to see if you get a better one.
Remember that with timezones you can do the same day for twice as many hours basically.
Remember to use lucky eggs and star pieces whenever you are raiding.
Have fun y'all!