(Yes I realise I overdid the healing items a bit)
There's three things in Red's arsenal that are particularly dangerous - Charizard, Venusaur, and the mass amount of Blizzard that his team possesses. The best way to win was to break down each wall.
Blizzard was handled by a somewhat cunning trick; namely, I changed the date to October 10th. On this date the usual snowfall at the peak instead turns into diamond dust, meaning there is no Hail within the fight. The elimination of Hail means the usual 100% accurate Blizzard that Red has goes down to 70%, so there is now much better chance of being able to avoid it.
I expected Charizard to try to take down Ludicolo with an Air Slash, so I equipped Ludi with a Coba Berry for a one time reduction when hit with a Flying-move. I used this same tactic with Lance, but since his Air Slash missed the berry wasn't used.
Venusaur I didn't really have anything specifically prepared for. I was intending to do a sleep and run strategy with Jumpluff and just use Exeggutor to murder Venusaur, but due to fast waking up times that failed. Roserade proved useful due to her neutrality to Poison, and going toe to toe with Venusaur with the aid of healing items proved to be the best method that wasn't too controlled by luck.
Lapras, Blastoise and Snorlax were not too hard to deal with. Lapras took a heavy hit from Grass Knot and then Leaf Storm which put it out of comission and Snorlax had its health sapped by Toxic; I had been planning for that strategy for a long time and was the only reason Roserade entered my team in the first place. Blastoise turned out strange as I was intending to deal with it by using Ludicolo (hence the Max Revive I used) but because Blizzard missed Tangrowth I ended up having a Power Whip vs Full Restore competition. At any rate, Blastoise eventually died.
Pikachu was easy. It always is.
With that I've actually finished a run, the first in a while. Now I need to actually do something non Pokémon related ffffff
Oh by the way here is the team info;
Meganium @ Silk Scarf - Rock Climb / Earthquake / Petal Dance / Reflect
Roserade @ Poison Barb - Grass Knot / Sludge Bomb / Shadow Ball / Toxic
Ludicolo @ Coba Berry - Surf / Ice Beam / Energy Ball / Rain Dance
Exeggutor @ TwistedSpoon - Leaf Storm / Psychic / Leech Seed / Sleep Powder
Jumpluff @ Muscle Band - Bounce / U-Turn / Sleep Powder / Leech Seed
Tangrowth @ Quick Claw - Power Whip / Focus Blast / Rock Slide / Sleep Powder