Yesterday a customer of mine with 100% water injection set up, this is one of my old systems fitted to a 12A (running cosmo top intake manifold!) Rotary street port running 18psi boost pressure.... (see non adjustable atomizer fitted in bottom left of pic).
He dyno'd 478hp @ the hubs on a dynapack chassis dyno = around 550bhp using the conventional 1.15TCF these specify.