Horizontal runs on gravity drains slow water flow pretty significantly. This may not be necessary, but just in case you run into an issue with your drains not being able to handle your pumps output, using a 45 fitting would probably increase your flow. In other words, instead of those two long horizontal runs, you would have downward 45 degree slope to your sump. Of if 45 degrees is too much, you could find a 22.5 degree fitting.
Just a heads up on that rigid insulation: the kind I used had a reflective sheeting on it. I placed it reflective side down (facing water) and it totally dissolved...the reflective material had basically disintegrated and made it's way into the water. I didn't lose any fish but it freaked me out. So now I wrap it in cellophane to avoid tha from happening again.
+1 on what was said about heating the tubing to straighten it out. I placed a roll I got in the sun and it was good to go within a few minutes.