It depends on the dimensions of the church space, just the sanctuary, or the narthex and choir loft, etc.
You need to know how many clients might all be on the wireless at the same time. Space your APs far
enough apart to cover the entire area you need, ie on walls around the area(?), but do not put your APs
right on the metal framework, I-Beams(?), if thats what you're asking about the "studs".