As far as this topic goes,
Sanshiium's recent passive cleaner might be very well be FPS-best dwarven bathtub.
You can get rid of the standing wave and make it wagon-capable by using 4-wide design, letting it drain once and then adding 5/7 water for 2/7 on every square.
The aquifer requirement does make it not workable for low water embarks, though if you have large murky pools map edge fortification drains also work, getting marked permaflow (interesting difference from portable drain).
This works even after being dammed and dried out.
@taptap:
Checkpointing to the end of flat track after it - mainly, shaves off time to cross that particular tile down to 1 step. Otherwise, the cart would cross the tile in...something like 3 steps?
Might also lower the jump speed (because the cart starts as deep into second NE ramp as possible) compared to two NEs after one another, but that one might have been usable too, just not as efficient.
I say might, because it
has been over half a year ^^;;
Never used it for magma mist showers, though - I suppose if you're bringing up magma by minecartful, it fits very well "very limited", though it is bit clumsy to tile, what's with those NE ramps - replacing the flown-over floor with fortification, you'd have kinda zigzagging thing. Would make me want to have a single magma trench where carts skip in synchronized motion, each one using 1 tile of the trench, if mass-producing it. On the other hand, single point mister would work very well, where do you utilize them?