Yeah, I use an office chair as well. I just remove the armrests. I also try to avoid those ones where the back curves in towards the outer edges. Those ones usually scratch my guitars' backs up.
The good thing about office chairs, I find, is that you can rest your back on, but you also have some control about how far up and down they sit.
I mean, after all, office chairs are supposed to be ergonomic for being seated in for long periods of time.
However, I will say that if your goal is to make the transition between playing seatd and santing up seamless, office chairs might not be the right way to go.