One thing I always try to

One thing I always try to do (if possible) is to plug into the house audio (if they have someone running a mixer). Talk to the representative from the church in charge of audio. Most churches will be using much higher quality equipment than I can afford and the audio almost always comes out very, very good. If you go this route, make sure you have a backup. Use a MD recorder or at the very least a good shotgun mic. I’ve never been burned by the house audio but you never know. This also means that you are banking on the operator knowing what they’re doing. (You should also try to provide any cables you will need instead of asking the church to do what is really your job).