Yes, more layers are better, as is a larger area.
But how do you make it work with the pressure plates? don't they get washed away with the water?
And as Sor says, you have to be a bit away from it. I think 20 ish blocks or something (which works in any direction, up, down, sideways, essentially a sphere centered on you with 20 block radius).
EVE Online characters:
Daedalus II ex-CEO TOGOA, Daedalus III slave of Daedalus II
Little Molok Asura Engineer
"Each day I don't get an attempt on my life by a robot from the future I see as a personal failure"
Last edited by DaedalusAlpha; 4th February 2013 at 02:15 AM.