Just recently, I bought a Manfrotto 190CX3 and a 488RC2. The lightweight combo worked great for my Hasselblad 501C.
[QUOTE=Greg_E;654975]The cut out part is normally filled with a rubberized cork material to help prevent things from turning.
Actually the one in the pic is specifically for the 'Blad. The one you're referring to had a hex shaped cork or rubber insert.
The pic in the B&H ad has a ridge on the back edge that will protrude upward & not let the 'Blad sit flat. See if you can locate an original Hasselblad QR plate.
they fit any head & lock down very securely. They're also very compact & lightweight. Rather than use a two part gadget, the 'blad accessory Is a female, locking receptacle that the bottom plate of the camera slides into.
I have the 229/055CLB combo Ari, the 229 it's very smooth, yet a bit heavy and together with the 055CLB, nothing impossible, but surely not the lightest setup around.
I've used ballheads before with my Blad, I surely prefer this 3D from manfrotto, go for it, I'm sure you will be happy!
I have the 229 head with the standard hex quick release plate. I bought this head specifically to make sure that it could take the Hasselblad weight and size with the 80mm lens attached. I was going to fork out for the special Hassy quick realease plate but i decided to go with the standard plate initially and then, if there were any issues, i would then buy the special Hassy plate. I have had no reason to change the plate. The standard plate that comes with the Manfrotto 229 head works beautifully as does the head itself. It is quite heavy but extremely stable and precise. It never feels loose. I have stood on windy cliffs and windy beaches and it has been rock solid. I am using it with the Manfrotto 055XProB tripod legs. The head is built like a brick shithouse and did i mention that it is solid? It is easy to use with the hard rubbery handles on each of three controls and has spirit levels up the wazoo. It also comes with a 3/8" and 1/4" screw on the plate for camera mounting. I use the 3/8" screw for the Hasselblad and the 1/4" for my smaller camera.
I recommend the 229 head and standard plate but if you really want to be sure then, by all means, buy the 229 head with the Hasselblad plate. I have found that the standard plate works fine (and works with all my other non Hasselblad cameras too).
I'd be very interested to hear how your results compare.