Team Great Scarf (GS for short) (PtHGSS Battle Tower)

[Tombstoner]

So, I was a bit disappointed with the results of my last Battle Tower team (Uxie/Scizor/Garchomp.) I scored 101 wins, but only after many retries. I want to change that for the next time. Here is the new team I'm planning to use:
Slot 1:
Either
@ Choice Scarf
IVs: 31/x/31/x/31/31
EVs: 252 HP, 4 Def, 252 Spe
Nature: Bold
- Trick
- Thunder Wave
- Charm
- Flash

or
@ Choice Scarf
IVs: 31/x/31/x/31/31
EVs: 252 HP, 4 Def, 252 Spe
Nature: Bold
- Trick
- Thunder Wave
- Charm
- Flash

The two best leads known to exist. Neither of them draw Ground moves (good for Drapion,) and both can draw Dark and Ghost (again good for Drapion.) Whether I want better defenses or Ice weakness depends on the third member.

Slot 2:
@ Black Sludge
Ability: Battle Armor
IVs: 31/31/31/x/31/31
EVs: 252 HP, 56 Def, 196 SpD, 4 Spe
Nature: Careful
- Crunch
- Acupressure
- Substitute
- Rest

The god of the Battle Tower. Didn't use him before because spamming Acupressure makes for very long battles. His type goes well with both Mesprit and Latias, so he's the member that's definitely going to be staying.

Slot 3:
Either
@ Lum Berry
IVs: 31/31/31/x/31/31
EVs: 252 Atk, 4 Def, 252 Spe
Nature: Jolly
- Earthquake
- Outrage
- Substitute
- Swords Dance

A faster option to send in against locked 5 PP moves. 31 IVs and 0 EVs at Lv.50 gives it odd HP for four Substitutes at maximum.

or
@ Leftovers
Ability: Sturdy
IVs: 31/31/31/x/31/31
EVs: 251 HP, 252 Atk, 4 Def
Nature: Adamant
- Steel Wing
- Aerial Ace
- Substitute
- Swords Dance

Now, before you all go crazy on me for considering this, let me simply tell you why he's up for consideration. While Garchomp gives Fire and Electric resistances, Skarmory's Steel typing gives it many resistances, as well as a Poison immunity (Ground too, though the opponent should never be locked into those.) Steel Wing and Aerial Ace help deal with the Mold Breakers (Rampardos and Pinsir.) However, the main reason I chose this was that it had Sturdy, along with decent enough Attack and Defense to run for Garchomp's position. OHKO users would be the team's main threat, as Choice Scarf allows them to potentially sweep the team (happened to my old team with a Lapras once before even reaching 49.) Sturdy eliminates that weakness. You know another weakness that's destroyed my team before? BrightPowder and Lax Incense. Aerial Ace takes care of that, though. 251 HP EVs for odd HP.

How do you think it would do? Which Pokémon for the lead and third spots should I pick? I plan to RNG them when I get the chance (and get started on doing it,) which is why they appear shiny here, with all needed IVs.