It should be fun because that is real 6x6 MF size, the look should be un-surpassed!
LOL, that should set them wannabee (cropped) 'MF' sensor boys straight...
Shooting true MF@56x56mm (or 56x70mm) with Portra 160 should be fun (I think I still have some '120 spool' rolls in the fridge), just give it a bit more exposure for better scans. Shooting it as ISO 160 gives rather modest density, more density is better for scanning. I used to shoot it as ISO 125 even when I did C-prints, but scans have no problem with even lower ISO ratings and normal processing.
P.S. I've added some common filmscan sizes to the camera pull down menu of my on-line DOF and Focusstacking tool. Resolution on filmscans is not as clear cut as for a direct digital capture device, so I have not included scan resolutions that are only needed to avoid grain-aliasing or artificial upsampling.