I have an 84% Jynx with Frost Breath/Avalanche. Worthy of the dust to go from Lv. 20 to Lv. 30 specifically to kill the ubiquitous Dragonites around me?
Answers
Piloswine's better in my opinion since it has more HP so it'll do more damage before fainting than a Jynx will, useful if you're facing multiple Dragonites or happen to miss a dodge.
Also Piloswine has a higher chance of getting the moveset you want, because both quick moves are ice and perform similarly, while Jynx only has 1 ice type quick move. On both you definitely want Avalanche, but Stone Edge is okay on Piloswine, same with Draining Kiss and Psyshock. Avalanche is much better, but it doesn't make them unusable if you don't have them.
If youv'e got lots of Swinubs in your area would say just evolve any high level Swinub until you get the moveset you want, you'll save yourself dust from not having to power up. Where I am, Piloswines usually take up 4 or 5 of the 9 nearby slots, but it might be different for you.
Also Piloswine has a higher chance of getting the moveset you want, because both quick moves are ice and perform similarly, while Jynx only has 1 ice type quick move.
In case you did not read the question, or you read it and did not understand it, i want to point out, that the op already has got a jynx with the desired Moveset.
Personally I'd save my stardust. Not sure about where you are, but Jynx's are fairly common where I am, I've picked up a couple around lvl 28-30 with double ice moves. Also, as has been said, Piloswine is probably just as effective and generally quite readily available. Plus having attackers at prestiging level is just as useful as having them maxed out, so I'd keep her for that.