1) It's not yet. It will be in SB2.#1 - Is Custap Berry implemented on Shoddy Battle? Maybe I'm just stupid, but I can't find it.
#2 - Would something like that work:
[You're in a bad situation. Gyarados has a DD, your counter is dead and your checks are weakened, so they can't take a hit any longer]
You have a steel/rock/ground-type (something immune to SS) wearing a Custap Berry. Can you endure on the Waterfall, kill and outspeed it? Or Am I misunderstanding the mechanic of Custap Berry?
[As example: You have a Ramparaods (lol) with Endure/Head Smash/EQ/whatever. Obviously you can't outspeed Gyarados and Waterfall will kill you. You endure on the Waterfall (no Gyarados will DD/Taunt against Ramparados) and outspeed it with the help of Custap Berry]
#3 - Does something like a "speed calculator" exist? I need it for the purpose of creating new movesets. I always get a headache when I'm testing how much speed I need to outspeed certain Pokémon. (PS: I know the link to the speed tiers, don't post it).
Thank you.
-0²
2) That would work fine.
3) Not really. You sorta have to use your own calculations. It's basically just add one, subtract from the minimum speed stat of the Pokemon you're using, then multiply by 4. If you're using a positive-speed nature, add 1, divide by 1.1, round up, subtract from minimum speed stat, then multiply by 4.