I shot weddings on MF for years initially just using a Mamiya C330f before moving on to a Hasselblad 500CM. I usually shot 5x rolls of Fuji NSP160 (60 images) in the later periods I pretty much exclusively used 120 sized Fuji Reala.

There were no film backs for the Mamiya C330f and I learnt to change films pretty quickly. RH suit pocket for unused films and LH suit pocket for used. I opened each film from its box and foil packaging before I got to the wedding so all I had to do was undo the sealing strip and insert into camera.

When I got the Hasselblad, I was spoilt with having 2x A12 backs which made life a little easier but you could not always guarantee that they would not run out at an inopportune moment.