Worship playing looks like it should require reading. In practice, almost none of it does. What it requires is being able to follow.
A chord chart tells you what, not when. The when comes from listening to the person leading, which is why players who learned by ear often settle into a team faster than players who learned by reading.
A leader dropping a song a tone is normal, and it is why we teach shapes rather than fixed finger positions. If you know a song as a set of relationships between chords, moving it is a matter of moving your hand.
The hardest thing for a new team member is playing less. Two guitars, keys and a bass all filling every gap turns into noise. Learning what to leave out is a skill in itself, and it makes you the player people want back.
