I'd start wherever you shoot Portra and it should work fine.

Extra exposure doesn't hurt a thing with this film but isn't required and as others suggest avoiding underexposure is a good idea.

As to the color issues mentioned, yes it has a different pallet than Portra, and yes it needs different settings to print. That's a big so what moment for me; just like Portra, once you get it figured out its really nice for portraits or whatever.