Levels of Distractibility: Who cares? = *. Some people will be distracted from your meaning: = **. Many people will be distracted from your meaning: = ***.
Question: If I use "Either," will the verb that follows be singular or plural?
Answer: "Either...is...." Either by itself is singular and takes a singular verb.
"Either a plane or a train is a good way to reach your destination." If both subjects, plane or a train, are singular, the verb that follows is singular.
"Either planes or trains are good ways to reach your destination." If both subjects, planes or trains, following Either are plural, planes or trains, then the verb is plural.
Let's simplify: If you have a compound subject, make both subjects plural (followed by a plural verb) or singular (followed by a singular verb).
Rating of Distractibility: ***. The only complication is if you use a singular subject and a plural subject in the compound subject. Then the subject nearer to the verb requires a plural verb if the subject is plural and a singular verb if the subject is singular. But all of that is silly and creates problems. Make both subjects singular or plural and use the appropriate verb. You can't go wrong.