Colby,
The 48 chainline was developed for frames struggling to optimize for tire clearance, but we solved it without the need for a wider chainline, so it’s better to stick with the 45.5, especially if you’ll spend more time in your easier gears. A wider chainline will increase drivetrain noise / drag in the granny gear because your chain is going to be more “stretched” diagonally the wider you go, but it would still be functional and useable. So, there is no truly wrong answer, but 45.5 seems better.
Stephen