Sch 40 is just fine. If you want it in grey insted of white you can order grey sch40 from usplastics.com
Edit, adding;
Also (and partially in response to your PM last night) a good trick is to cut down the fittings a bit on the duroso so that it takes up less space. The place to cut down is center socket on the T, and one end of the eblow where it connects to that center socket on the T. In other words, the part of the duros that sticks out to the side from the standpipe itself can be cut down to it doesn't stick out as far. The sockets get tighter when you cut them down, but you can sand the pipe a little if it gets too tight.
LMK if this was hard to follow or make sense of, I can find a pic somewhere if needed.