Toilet Rough-in on Slab

I am currently running the drain lines for my bathroom remodel and have a question about the toilet rough in. First, my understand of a 12" rough in is 12" from the finished wall to the center of the flange, correct?

Also, I am on a slab so I will be running the drain lines, then pouring concrete around them. I do not know the height of the finished floor as my wife has not decided on the tile yet. I recall reading somewhere that if I have a 4" line, I can install a flange that mounts inside. I was thinking I would just run the 4" PVC pipe up about 6" above the floor, pour the concrete, and cut it back to length and glue the flange in. Is this correct or is there a better way to go about it?

Pipe up about 6" above the floor, pour the concrete, and cut it back to length and glue the flange in.

Click to expand...

That works for me.
Don't forget the vent and the cleanout.

drain

I install the pipe high, place a cardboard sleeve around it to space the concrete away from the riser, the use an "outside the pipe" flange. After it is slid down the pipe onto the floor the pipe can be cut off flush with the top of it.

I'm running with Terry on this one. Your mileage may vary!
Just started the finish on a movie theater. 8 toilets in the mens all with 4" stub ups and inside the pipe flanges.Used plenty of glue and most failed a final!
Had to wax the inside of the flanges to hold the final test!
(Score: 1 HJ 1 Terry.)