My roughin for my basement washroom has my toilet sweep 90 elbow sitting 1 and 1/2 inches above the cement slab. I have purchased a toilet flange that fits inside the elbow but even if I cut this and the elbow down the flange would sit about an inch above the floor. Are there any recomendations as to getting my toilet flange resting on the finished floor? The elbow is abs or pvc (i'm not sure). I'm finishing the floor in ceramic so that will get me up 1/2 inches with thinset. I would rather not go much higher as the room entering it will be laminate and I want to avoid the drastic transition (i.e. around an 1 inch).