Pokefans please help! Part 2

See, my Unova Nuzlocke team need to train to face the Elite Four for the final time. It's the same general idea as last time, except this time length of time training is no problem, but rather, challenge. Here are the details of the Elite Four:

Every member of the Elite Four's guys are level 71, except for each respective final Poke, which are level 73. The Champion's team is all level 75, and his final 'mon, his Volcarona, is level 77. So to recap,

Elite Four:
71, 71, 71, 71, 71, 73
71, 71, 71, 71, 71, 73
71, 71, 71, 71, 71, 73
71, 71, 71, 71, 71, 73
Champion Alder:
75, 75, 75, 75, 75, 77.

You can go here to see their teams in full detail (though I'm only fighting the post-national-Pokedex-Black-and-White-rematches).

With this in mind, which level to I train everyone to? I don't wanna be so powerful that I ace them without any challenge, death, drama, or a speck of effort whatsoever (yes, I want death. This Nuzlocke isn't good for my mental health, apparently. XD), BUT I don't want to be flattened, rolled up and tossed aside, either.

Which level would you recommend? Keep in mind, their guys are PRETTY powerful, but then, so are mine. They have tough moves and stats, but we're the only intelligent team this side of the Transformers. And we're tough.

My Team Summary: (Subject to change)

Jade - Leavanny, Female
Leaf Blade, X-Scissor, Bug Bite, Swords Dance
Ability: Chlorophyll, Held Item: Miracle Seed

Tribble - Cinccino, Female
Sing, Encore, Tail Slap, Wake-Up Slap
Ability: Technician, Held Item: Rocky Helmet

Lwaxana - Galvantula, Female
Sucker Punch, Discharge, Bug Buzz, Slash
Ability: Unnerve, Held Item: Leftovers

B'Elanna - Seismitoad, Female
Surf, Drain Punch, Bulldoze, Strength
Ability: Swift Swim, Held Item: Poison Barb

Tanis - Krookodile, Male
Foul Play, Earthquake, Dragon Claw, Outrage
Ability: Intimidate, Held Item: Dragon Fang

Tal Shiar - Bisharp, Female
Night Slash, Swords Dance, Iron Head, Guillotine
Ability: Inner Focus, Held Item: Blackglasses

Any questions, suggestions, or a good idea of what level I should train to? Any help is appreciated! Thanks!

Higher than 80

Yessss; Tanis is still alive and kicking~ ;w;

*Ahem*
If you reaaaaaally want a challenge, maybe level 75? I'm not sure if that's a particularly good or bad idea, though. This probably isn't a good comparison, but earlier, I re-challenged the Kalos E4 with 6 Pokémon who never faced them before. Most of them were several levels under even the E4's Pokémon, never mind the Champion's, and they stood their ground fantastically; only one fainted, once. (The only Pokémon who was at a higher level was my dear Garchomp, Magnomalleus, at level 80, but he never participated in any of the battles at all.)

I'd say just stick with level 80, maybe slightly lower if you're willing to risk it. xD /I have no personal experience so

78-79 then, or 77

Rest in peace to all of them
They will be greatly missed and never forgotten
</3

They died? D:

Unfortunately, yeah /super late whoops