Learn how to arrange.
No one knows your teams better than you do. If you don’t know how to use notation software, I hear that Sibelius is very easy to learn and use. I use Finale – and the reason I don’t switch is because I spent FAR too much time learning Finale, and all of its in’s and out’s. That’s not to say that it doesn’t have its challenges though 🙂
Spend some time learning notation software, and arranging music the way you want your vocalists to sing it, and your instrumentalists to play it. Providing your musicians with clear consistent charts is crucial to respecting their time, and increasing the musical quality on a weekly basis. If your guitarists know that they’re going to get clear instruction, they’re more likely to be successful for you and want to come back.