Use of the Simple Future in the If-Clause
Generally speaking, the simple future should be used only in the main clause. One exception is when the action in the if-clause will take place after the action in the main clause. For example, consider the following sentence:
If aspirin will ease my headache, I will take a couple tonight.
The action in the if-clause is the aspirin easing the headache, which will take place only after the speaker takes them later that night.
“Were to” in the If-Clause
The verb phrase were to is sometimes used in conditional sentences when the likely or unlikely result is particularly awful or unthinkable. In this case, were to is used to place emphasis on this potential outcome. Consider these sentences:
If I were to be sick, I would miss another day of work.
If she were to be late again, she would have to have a conference with the manager.
If the rent were to have been a penny more, they would not have been able to pay it.
Note that the emphatic “were to” can be used to describe hypothetical scenarios in the present, future, and past.