No I do not use a roll back. If I am going to carry around a 4"x5" camera, then I am damn well going to shoot 4"x5" film! I have Hasselblads for 120 film.
that's great if you want to use a hassy and modern glass
but if you want to use a RR or tessar or anythining else that isn't modern with a hassy mount
you are hosed. a series d rb as you know isnt' very heavy, is perfectly weighted and can be used
as a weapon to clunk someone on the head with if they try to mug you .. it has shutter speeds from below 30thS to above 250
and its pretty much the perfect camera .. no reason not to use a roll back on IT, or any other large format camera.
i used to have a 35mm recomar back i used as a 4x5 reducing back. it was PERFECT and was a blast to use and
get perspective control 35mm images with schneider glass, wish i still had it
...as i said, film is film
who cares what camera it is used it, i find purists to be, ... well too pure.
and history has shown that family lines that keep their lineage "pure" end up with lunatics ...