hi , 883 to 1200  reversed dished pistons are the cheapest & easist  to work with  e,g S&S.           if you don't mod the heads  to suit it will be too  much comp ,  with the flat top pistons it will be 11,4 to 1 C.R.  with reversed dish pistons it will be 10.6 C.R,  you still have to take some out & c.c. the heads up . that at zero deck height ,    i set -up  at  9.7.C.R with  andrews N6 cams works well ,              or for more & more  $  for buell thunder storm heads , N6 is close to buell cam anyway  ,     cheers