Can I set up a service in advance?

Yes. This is done using the Play List feature. You can store as many tunes as you like in a Play List, personalising the settings for each tune (number of verses, style etc) as you go. When you have finished, give the Play List a name (maybe the date of the service). Then create more Play Lists for other services - you can store as many Play Lists as you want.

We have customers who retain all their Play Lists, effectively cataloguing their music use ever since purchase.