You can ask them. In fact, it would save you and the members of the congregation much frustration and take the guesswork out of the equation. Ask them:
"What kind of hymn introduction is used in your church? First phrase, last phrase, voices entering one by one, choral fughette? And what about the registration? Is every stanza played on different combinations - principals, flutes, strings, reeds, mutations, full principal chorus with mixtures? Where is the hymn tune placed - in soprano, alto, tenor, or bass? To encourage the congregation to sing the next verse on time, what kind of rest is used at the end of the previous verse? What kind of exposition is used for the prelude? Binary or ternary? What kind of modes and tonal plan is used for postlude toccata?"
If they can answer this, then go ahead and tell them, "yes, I'll do it your way."
Chromatic sequence in F major: I-V43/vi-vi