Warhammer 40K Tabletop XXXII: I Got 99 Guardsmen and Morale Killed One.

[Cheesegear]

Alright. Dark Eldar Troops. Keep in mind that this is pre-Codex. So maybe don't go out and deliberately buy something because I told you to...

Kabalite Warriors: At a whopping 7 points each, they're pretty cheap. Don't be fooled, however. Against Guardsmen, they have no better than a Lasgun. Against Sisters, they still have Lasguns, but now the Sisters gets their Power Armour save and it's totally different. Where Kabalites start getting good, however, is in 'Marine metas', as now Kabalites now carry Boltguns for 7 Points. That's less than everything else, and that better chance To Wound, combined with only being 7 Points each, makes Kabalites better than anything in the <Imperium> for killing Marines. Unfortunately, as good as Kabalites are, they aren't even the best unit in their Faction...

Guardian Defenders: Guardians are 8 Points each. Gross, right? Unfortunately, they come stock with S4 weapons that occasionally ignore Armour as well as a Plasma weapon. Baller. At 12" range, with Assault weapons with Battle Focus (we'll come back), Guardians are one of the strongest units in the game - including Guardsmen! Whom they're actually equal to! - and from there they only get better. The biggest issue is their 12" range. At 12" range (that's Charge-ranged for most units), they dominate the game. Those 'every other shot is Plasma' Shurikens really know how to hurt. Outside of 12", where most units lose their Rapid Fire double shots and their effectiveness is basically halved, Guardians' effectiveness drops to 0. Making them literally the worst. 7" Elf Move doesn't even help because 12+7 = 19, still falling short of the standard/good 24" threat range. So there's that. But Shurikens are Assault weapons. Great. You've got Battle Focus so you wont take the -1 To Hit, but you'll still need a 5+ on your Advance dice.

Good news is that you're Ynnari, so you can pick whichever you want.

Wyches: Wyches are a Melee unit that can't be in Melee on Turn 1. Don't waste your points.

Wracks: Wracks are a Melee unit that can't be in Melee on Turn 1, and prevent you from taking the Ynnari Faction on your Detachment. Absolutely don't waste your points.

I'm considering attempting to run a narrative tournament at my local gamestore. Does anyone have any recommendations on how to select what missions people would be playing, how to score the missions, and how to determine the attacker and defender?

I assume you've read pg 272-73 of the rulebook? Always start there.