Just so you'll know what a martyr I am for my art, I weighed the Mamiya yesterday. Turns out it weighs 4 pounds! For comparison I began weighing other cameras. The Great Wall weighs 2 pounds and the Lubitel 2 just over 1 pound. My right arm is going to be very muscular by the end of summer.
I finished a first roll in the camera. Barring the weight (which has practically broken my thin wrist) it's a gem to use. I took lots of close-ups and remembered about parallax shift after it was too late so who knows what I'll get.