Okay, i just finished my runthrought, and its rather weird
Oh yeah, before you asked, i actualy beat Johto Gyms with several pokemon. You can see some solo-ing data here because i abused Save State to rematch the Leader.
As for Kanto Gyms, i soloed them except for Brock, Misty and Blue because i need the EXP.
Starter:
Chikorita: Chikorita is pretty great, it can handle Rock/Grounds, its water resistance are EXTREMELY useful, and it gets rather good moves from Level up. To use Chikorita, i give it cut for Staple Normal Coverage. It has bad early gym matchups(i lucked out against Bugsy and it does nothing against Morty, so-so match up with Pryce), but it is the reason why i manage to defeat Claire, underlevelled.Oh, and Para Hax Body Slam FTW. Meganium is not that bad in Kanto, but it does rather badly against Red.
End Gamelevel: 51 w/ Body Slam, Cut, Razor Leaf, Light Screen
Current position: High Tier
Used Pokemon:
Spearow: The Boosted Spearow did not do much in my run, but it is the mon i used to beat Chuck's team. Starting at level 10, i grind 3 level or so on it, and use it to handle Morty's Gym. In general, it has good route match ups, and rather easy to grind. It is notable for outspeeding, and solo-ing Venusaur, something that normally takes time. It learns Drill Peck against Koga, at level 40/41.
End Game level: 52 w/ Drill Peck, Fly, Pursuit, Fury Attack.
Phanpy: Lucked out and got a Phanpy. To be honest. Phanpy is rather pathetic until you get acess to Roll-Out and Headbutt. And then, Phanpy does not become perfectly usable until Donphan. Even then, Donphan has the pathetic movepool of *generic normal type + Roll Out" and EQ at 49(It should be noted that you can catch Donphan below Blackthorn at reasonable level(by GSC underlevelled standard)
Donphan actualy did not start to become awesome until Kanto, where it can grind off several gyms, and the trainers. So, why use Donphan? Because with Defense Curl, and Roll Outit counters Red's Snorlax thats why(and Snorlax is arguably a massive threat otherwise). Without Donphan, thats 15+ Full Restore to waste against Snorlax, who Donphan can beat with MUCH LESS Full Restore
Endgame level: 50 w/ Rollout, Defense Curl, Headbutt, EQ
Current position: Mid Tier
Pineco: Just here for lulz. Catch at level 10, grind to 11, use Selfdestruct against Miltank. Kill that ****
Magnemite: When you look at it, Magnemite is simmilar to Tauros, except its common. So, your having a Steel/Elec who loses to Rock/Ground, lose to Fire, and can lose to Water Type, and it has pathetic movepool without TM. Low Tier? Nope. Magnemite can get an easilly resonable level despite its bad match up, and it level up easilly. However, it also carries the Typing that allows it to handle SO MUCH THREATS in the whole game. In particular, its Thunder Wave are the key of defeating Lance Level 47 Dragonites, and Red's Espeon. Magnemite did not perform well in battles, but its typing allows it to laugh at many stuff.
Endgame level: 48 w/ Thundershock, Tri Attack, Thunder Wave, Sonic Boom
Current Position: At worst High tier.
Nidoran Male: Caught at Goldenrod Park, i used it to handle the park and it become Nidorino. I grind it until 21 and give it Moon Stone after i can use Surf. After that, wins against Jasmine, loses to Chuck's Poliwrath, struggles against Claire, and does Jack agains Pryce. Thankfully it has good route match up to catch its level, and Elemental Punches. Nidoking did not become notable until it defeated Lance DNite with Para Support, and many easy Kanto Gyms. In general, it has 4MS Syndrome. Surf for R/G(Ice Punch is actualy too weak) Thunderpunch for Waters. Fire Punch for some mons that i forgot, Thrash/Something for Normal Coverage, and it can learn EQ for STAB. After Lance, it has decent Kanto Gym Match ups.
Oh, and it does Jack**** against Red unless you want to easilly handle Pikachu that badly, so i left this thing. Seriously, Nidoking sounds good on papers, and seems to be as good as its RBY version, but its actual performance is not that good.
Endgame level: 48 w/ Thrash, Ice Punch, Double Kick, Surf
Current Position: High at best
Tauros: Yeah, this playthrough was to test Tauros in the first place. Put simply, it owns. I used a minimally TM'ed Tauros, as in Strength and Surf. It easilly raises its level with the route 38 Trainer, and i give it Strength. Then, it almost solos Silver in burned tower, actualy beat Morty's Gengar with Surf at level 22, Easilly solo-ed Pryce at 28. It struggles against Jasmine, as my match-up chart above states, and it 2 shot Dragonairs, and get 2shot by Kingdra.
In Indigo, its high speed and power helped against Jynx and the Lead Xatu, at it handles most of Karen's team. Sadly its rather bad against Lance.
In Kanto, Tauros can easilly solo like 6/8 of the gyms, and decent against Blue and Brock.
Against Red, Tauros 2 shot Pikachu who 85/100 of the time did not do any damage in return. after that, it goes downhill. It gets 2HKO by Espeon, but its faster, and 3HKO with Strength. However, it is the best choice to kill Espeon with after Espeon gets paralyzed. It, basically loses to Red's entire team, although being able to survive 2 Flamethrower is pretty cool
I admit, taking Pursuit is a big mistake, Scary Face is MUCH better. With Scary Face, Charizard become easier after Tauros survived a Flamethrower...
Endgame level: 53 w/ , Horn Attack, Surf, Strength, Pursuit
Current Position: High Tier
Snorlax: I admit this thing is a late game addition that does ABSOLUTELY NOTHING so i wont tier this thing. It comes at level 50, and suddenly become my highest leveled pokemon, and i store this thing. That is until Red. Against Red, it gets 2HKO by Rain Dance Surf from Blastoise, and 2HKO by Flamethrower which is exactly what i need to stall the Flamethrower and Surf PP. Hell if you get a Parahax from its Body Slam, you can pretty much win against Charizard and Blastoise
Endgame level: Level 50 w/ Body Slam, Rollout, Surf, Rest
So, what is the standard level for fighting Red anyway? If its based on my run, Red was basicallly impossible to beat without at least 55 Full Restore and 33 Revives