More info----are you willing to give up a closet?
Hey Mike, think I am just going to leave the cast there. Ive decided not to re-arrange to much. And I dont want to have to remove that pipe.What is the plumbing wall like down stairs? I might be necessary to open the wall enough to pop the cast iron stack (cut with a chain breaker) so you can convert to PVC.
Breaking the cast iron will allow you to rearrange thing much more easily.
You tub is plumbed in 1 1/2" ---a shower is 2"---go figure.
---Mike---