Currently they both have to pull through a 180-degree bend, which reduces the efficiency quite a bit. They also have to go into pain-in-the-arse-to- reach soffit vents which then point *down*.
So the thinking is to change the fans orientation to vertical, and have one pipe in - straight - and the other out - straight until it goes into the roof tile.
It's a concrete tiled roof, if it matters. I am starting to develop an aversion to anything sold as "universal", so is it best to get a specific vent for the tiles on my roof (Redland Stonewold II) ?
And, of course, any "gotchas".