No need for Sched-80. 40 is just fine and a lot cheaper. If you use quick disconnect uions they are probably sched-80. May consider short sections of auto radiator hose right on the PVC pipe. You can get straight 3' sections at almost any auto store and cut as needed. Go with the cheap stuff. Some hoses can run $40 a section but there are cheaper ones that aren't reinforced as much and work just fine. I have a pic in this thread where I used it on the pump outlet line. Same hose in 7th or 8th season now and no signs of deterioration.

http://www.poolforum.com/pf2/showthread.php?t=7054

Hose would allow some flexing and if used on the pump it cuts down on conducted noise.
Al