I used one for weddings for years but you are right it is quite heavy hand held, especially with a Metz 60CT added.
I should ask are you using any hand held bracket or just holding it by the bottom. If that is the case the Hasselblad bracket or aftermarket bracket may help you. I had the Hasselblad bracket, and used it ocasionally without the flash and it wasn't too bad.
I use a Mamiya 7II now for personal hand held stuff and I have friends with Pentax 67. Both are much better and eaiser to use handheld, in my opinion. I've never used a Rollei.