I built a siphon with 4" and 6" corrugated landscaping tubing. The 100' long rolls you see at Lowes etc. They sell a fabric sleeve to put over the pipe to keep soil from going into your french drain system. I put a 4' spur of the type with holes in it with a fabric sleeve over that and tied off the end. With that down in the water on the draw end, nothing solid got out.
Low pressure is created by the rise to the top of the hump of your system. You'd definitely not want flex / thin wall at the top of a high-rise system. Sounds like you're not using large elevation gradients and may get away with it near water level.
