As my trade is a movie theater technician, I have developed the habit reading manuals and doing my homework before I do anything.
Up to this point, the only 120/Medium format cameras I have used are a Yashica Mat and a Zeiss Ikonta. On both of those, you align the arrows on the film leader to the start mark on the edge of the film gate.
Previous to this, the only experience I have with MF is second hand. I only watched other people do it. My own experience has been with 35mm, up to this point. Honestly, I'm really liking it.
Probably my most favorite thing is the fact that the ƒ-stops do not have detents. I like taking my meter readings, incident, highlight, shadow or mids then being able to use my judgment to decide on the final aperture setting. I'll often take a meter reading then look at the scene again and decide, "Hmmm... Just a little bit more." I like the way the camera makes me THINK about the picture I'm going to take. When I go back to using the 35mm, I do even better work because I have learned to think about photography.
No matter how much of a fan you are of digital photography, this is one thing that you can not learn on a digi-cam. Even if you plan on shooting with digital cameras for the rest of your life, I think you should spend one summer shooting with nothing but a Rollei. By the time you go back to your digi-cam, your photography skills will have increased tenfold, if not more.
Don't worry... I'm not going digital any time soon. I have too many good film cameras, half of which I have barely even looked at yet. Among which is a Rolleicord and a Graflex RB Super D. I'll probably be dead before I ever master them all!
BTW: The 9 a.m. to 3 p.m., May through August thing was supposed to be a joke.