Breakpoints, bulkpoints, and rare candies

I've done 15 Mewtwo raids out of 22 invites and my best is 91%. 15a/11d/15. Moves are temporary, your 93% is the best quality of what you've listed.

However, groudon is coming back and Rayquaza is coming back (imo). How are your grass attackers and your gyarados?

For ray, you aren't particularly deep in the dragon dept, but rock and ice attackers do really well against Ray, too. The problem people have with Ray...three or 4 can consistently beat it...but sometimes Outrage happens and it can be somewhat close/take many revives etc.

You having missed out on those two is huge, so overreacting is understandable...I did 30 Groudon and 48 Rayquaza raids...that is near the median compared to the hyper raiders that pop in here.

You should probably put this current candy toward Kyogre...doubt that's coming back (I did 62 of them). In the future collect some more candy for that 93% Mewtwo. Collect Rayquazas and get RQ candy with some things you already have (try to avoid OR with small groups)

I'd ask yourself what you're going to do with them. A Mewtwo that's good for any non SB Mewtwo raids is nice, as well as being a good generalist. Kyogre is good against Regirock, and anything else weak to water - in the rain, it's actually a touch better than Machamp against Tyranitar, because of the high CP.

And while (if I remember correctly) your kids like Latios, it's not that useful in of itself. I use the SB moveset against water sometimes, but it's strictly a second tier attacker for that.

Another good option is to hoard some dust and RC, and see what happens. Maybe we'll get Groudon or Rayquaza after Regice before the other Regis are rolled out - that would be a good way to spice up an other wise boring run of legendary raid bosses. Be ready to power up something to counter whatever comes next that interests you.

Go for Kyogre. It will help a lot on the coming Regirock raids (and Groudon if he comes back sooner rather than later).
My advice would be to hold on to the rare candy till you find a better Mewtwo (because you can get them regularly). This because Kyogre has no use right now.
If you dont get a good Mewtwo till Regirock/Groudon, then power up Kyogre. If you have the bag space ofc.
What I do regarding breakpoints is leveling my pokemon on the go, depending on the current raid bosses. Regirock's breakpoints for your Kyogre are 27 and 36.5, so for now you could stop at lvl30, or if you find the candy till then power him up all the way to 36.5

I think the logical thing to do is get something to 30, then go for the next break point whenever a new raid boss comes out that you'd use it against.