Bottom contour for swallow

I am making a double bump/wing swallow tail shortboard. its my first attempt and it will be glassed clear. Fingers crossed. It will be a 3 fin thruster setup, but he wants a fast board and I am not sure if a single concave (which he asked for) will be best or whether a double concave with slight V at stringer will be a faster configuration. I haven't surfed a swallow tail so really have no idea, wonder if anyone could advise on the best options for bottom contours on a 3 fin swallow tail hipster?! thanks

PS> this is what i have in mind