Here is a pic of the test turret (an old DS Sherman turret) with the new hatches installed (very sloppy job! sorry!) The new loaders hatch is made slightly oversize as the original DS hatch is somewhat irregular.  It can be easily sanded to fit the opening.   I will add 2 small springs from some old pens to this later.   The commanders hatch unit is an old Viper one that we corrected (they had the hatches upside down! LOL!) and added the periscope unit to the corrected outside of the hatch.   These will not come on the turret.   You will need to cut off most of the old molded commanders hatch ring and install this new resin one.