Does it matter which order you take out and replace the batteries? And which order do you do the terminals in a dual battery system? Thanks!

Nope. I just disconnect both grounds, than both powers. Take the batteries out and drop the Optima's in. Reconnect both powers and reconnect both grounds. I've had one or the other or both disconnected quite a few times and never had a problem with the order.

Thank you for the info!