No, it's trial and error. As I mentioned, the "ideal" EV Spread of a Pokémon is dependent on what you want that Pokémon to do. For that reason, "ideal" EV spreads don't actually exist, as they depend on metagames and other factors independent of the Pokémon itself. So because EV spreads are tailored to the opponent, you have to trial and error with the opponent's moves to figure out how many EVs you need to tank the hit. Even Smogon's Dex Analyses don't have "ideal" EV spreads, they have "standard" ones. Depending on how you build your team, EV spread are often different to the ones in Smogon's Dex because different Pokémon are capable of answering different opposing Pokémon based on their EVs, and teambuilding is about having an answer to as many relevant threats in a metagame as possible.