If you set your devices to bitstream audio to the receiver, I would suggest leaving it set to AFD soundfield. If you have height speakers, you might wish to upconvert using either Dolby Surround or Neural:X.
It's more important to set up your speaker sizes and crossovers in the settings optimally. Even if you have large floorstanders, if you have a subwoofer, standard home theatre advice is to set your speakers to "small" regardless of what auto calibration says and to set your crossover settings at least 20-30hz higher than the lowest supported frequency of the speaker.
