Medium format over DSLR for weddings

Hello

I recently came across of the possibility to change my Nikon D3 for an Mamiya RZ67 with a Phase One P20 Digital Back.

I mainly shot weddings and products, and i use a Nikon D3 and D700 and a Phase One P40+. Good cameras with faster response (Nikon) and most of all never fail. My concern is to leave those aspects on my D3 for an system that can give better quality and slow down a bit.

So, using a D700 and two medium format cameras are enough to cover an entire weddings or its a bit risky to drop the D3 since i'm not really wanna go for the d800, d4 or d600.

Cheers

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Pedro Afonso www.pedroafonsofotografia.blogspot.com