The strain of the wave produced by BOTH of the black holes 
(added together) will be

            2GM                 1            v^2
    h  =  ----------    *   --------   *  ---------
             c^2                D            c^2


                                 1 
       =   30000 m      *   -----------  *  (0.25)^2
                             10^(25) m


       ~   2 x  10^(-22)