I was building my mock-up side yesterday and decided to use staples on the batten between the two pieces of siding. I, um, changed my mind about six staples in and thought, oh well, I'll just get out the 3" brick chisel and mallet and pry them apart. Nope. Staples are a lot stronger than I had given them credit for. Good thing it was the mock up.
I'm thinking I'll use a couple of screws first to establish alignment and allow for corrections, then staple once I'm sure things are where they are meant to be. As long as the staples countersink a bit, life should be good.