Robbie you should always use PVC for underground work. The acid in the soil will not eat away at it as it would the metal conduits. I also use rebar to support my ppie coming up out of the slab. And I will ALWAYS let at least 2 1/2 - 3 foot of pipe stick above the slab. This will lessen your chances of getting cement into you pipe and the other contractors will see it and not have it as a tripping hazard. When the time comes to trim your pipe just cut the pipe and the rebar flush. I also use a vacuum to suck my pull string through rather then fight pushing a fish tape around the corners.
Good luck, hope these few tips will work for you.
Bert
