OK. I guess I should post an update.
I was able to only rent the 503cw. They only rent the Mamiya 645 as a digital kit. I was able to hold it at the store, but I couldn't spend time with it and shoot.
On the 503 ... This is the first time I am shooting with Hasselblad. The WLF is giving me problems. It's not the inverted lateral view that is the problem ... it's staying level (side to side). When you combine the inverted view with leveling the subject, it gets confusing for my brain
. The 45/90 prism is out of the question for hand-held photography: too much strain on my wrist.
I have to say that it is one sexy camera, but I'm afraid I'm not going to get used to the way the image looks through WLF. Since I will not be shooting this camera all the time, I don't know if I will get used to it.
On the 645 ... While I only held the camera at the store, it seemed to be a little heavier than the 503. The ELF works better with that camera since it has a grip. I know that you can add a grip to 503 but it will add even more to the weight and cost. When you add all this up, an H system might be a better solution than 503 w/grip.
While at the store, I also played a little bit with a H2. That camera is so much lighter than the Mamiya and 503 and I loved the big viewfinder.
Now, is there any difference between H2, H2F and H2D in regard to functionality/build?
Oh, that RZ67 .... I don't know which term would better describe it: huge, humongous, tank ... that is definitely not a "on location with no tripod" camera
Thanks for listening and for the advice. It's really helpful.