Zargerth

Rorrim B should get his own signature move called Rorrim Shot

I've been raising some new Pokemon and playing Rejuvenation

Torkoal can learn Curse and Protect, so I was able to set up on Wigglytuff, then just attack Slaking with Flame Wheel and Protect. I guess you might be able to set up on Slaking if you just Protect yourself from it's attacks and use Curse whenever Slaking can't move.

I haven't played V6 yet (I have V5) so I don't know what changes have been made, but for me the most difficult fight ever was Narcissa. In my first save that has Reborn difficulty I went ahead and beat Valarie before returning back to Narcissa's gym, she was that bad of a monster. I assumed raising a Houndoom against her Chandelure was a good idea, but it didn't work out that well. Excluding Narcissa the leaders haven't been "OP broken whatever" even in Insane mode. Vivillon is surprisingly good for Venam as it learns Psybeam and is unaffected by the poison field. Torkoal, with 2 bottles of Fresh Water or so, can set up on Revenant Keta with Curse. I used plenty of Flying types against the regular Keta. I also like Technician Hitmontop + Triple Kick. You can also teach it Bulk Up after getting your 2nd badge, making it handy for Marianette. My Serperior utterly destroyed Valarie, and I guess Ludicolo with Giga Drain or Energy Ball does some real damage. Mawile and Jellicent were pretty helpful in Bug type gym (Stockpile + Baton Pass). Torkoal's Heat Wave was super useful in Angie's gym. The game is easier when you plan what you're going to do in each battle and raise the right Pokemon for the job. It might take some time but definitely pays off instead of trying to rely on luck in order to win, or worse, not win at all. Also, Leech Seed on one Pokemon and Fake Out on another mon actually is pretty hilarious when you keep switching. That's how I beat Shadow Mewtwo and that lvl 100 Yveltal.

I've been playing version 5, first at Reborn difficulty and then in Insane mode. Reborn difficulty has been useful for getting to know the leaders and their teams/strategies, and thus playing Insane mode hasn't been all that difficult now that I know what to do against them. I had to train some new Pokemon for some of the gyms, luckily it doesn't take that long. I would've had much easier time with the Water type leader if I had bred my Lombre, but I caught a male...also, Narcissa was already on Reborn difficulty the bane of my existence, I beat the Water type leader before her. Other than that, I've beaten the gym leaders in Insane mode on my first try or so.

Shade's Gengar knows Shadow Claw, so yes it knows physical attacks. If you're willing to use your Focus Sash, you could just lead with Shuppet (let it hold the Sash) and use Destiny Bond on the Garchomp. Unless you already have replaced it, Shuppet should know DB without any need for Heart Scales / level ups. You might be able to use Charge Beam and take the advantage of the field effect in play.