Countering Rayquaza: my limitations

Don't use stardust on cloyster/piloswine/Jynx. You can probably get by just with a level 30 one since ice-types won't have many uses outside of this.

Articuno is a good mon and I wouldn't really be worried about it being outclassed. Don't worry about maxing it - for now, try to just get it to level 30 since I can't imagine you needing one maxed asap.

Golem is only really going to be good for Flying movesets, and Dragonite will be better for Flying movesets too. Luckily, Gardevoir is a great answer to Dragon movesets. Ice-types can be used against Dragon and Flying sets alike, and Golem will resist the weak-base power rock set that is otherwise dangerous to Dragonite and Ice types alike

Personally, I would hold off on investing any resources into Rayquaza counters until it's confirmed as the legendary raid boss succeeding Kyogre. Right now, it's looking likely that it'll be up next, but until confirmed, I wouldn't spend any rare candies or dust.

That being said, do you have another Golem/T-tar you could use as backup in place of Raikou? If you get partly cloudy days with any kind of frequency, it wouldn't hurt to go hunting for some weather boosted Geodudes, find a big one, and evolve it into another Golem.

Find a high level Spheal in the rain and evolve it. That will perform better than Golem.

As stated above, make sure to not power up anything before it actually is there.

I went nuts anticipating on Mewtwo. End up being an ex-raid and I've never been able show off all my precious star dust in practice.

Hunt, particularly when it's raining or snowing. Last week I stumbled on a L35 Cloyster with IS/Bliz, and QTMd it to FB/Bliz. IV's aren't great (10/10/7 a/d/s), but for basically no investment, it's a pretty solid ice option at CP 2145, crushing things weak to ice despite its low HP, because of its ridiculous defense.

Walrein is also a solid option, close to Lapras, but less tanky and a bit higher attack (better for raids), and Spheals are everywhere, especially when it rains or snows. I've been unlucky with movesets so far, but hope to get 1-2 with FB/Bliz soon. Certainly a better choice than Piloswine.

And, being on team Instinct, I feel your pain. Getting 11 or more balls at a big raid is a big deal. I expect 10 if we own the gym, 8 otherwise.

We'll probably see Rayquaza on the 14th (or earlier), but the 20th will let everyone power up their dragon badges a fair amount, and evolve some nice L35 Dragonites that are a very good counter for non-dragon move Rayquazas. Or they could surprise us with the psychic dragons first, or something else altogether.

Piloswine is a solid counter and I wouldn’t overlook it. Has great moveset and fairly reasonable offensive breakpoints in the low 30’s. I caught several in the 30s during the ice event and plan to Tm and use them when the time comes.

Based on pokebattler sims Piloswine looks like the best nonlegendary ice mon to counter Rayquaza. It's got pretty much the same DPS as Articuno while having much more TDO than Jynx. Given that and Mamoswine, it's the non-Articuno ice mon most deserving of your dust.