evening Primrose oil.

how much is the correct amount to take ? l do not want to take them vaginally i tried that with my daughter it makes a huge mess. i would prefer by mouth. This is my 3rd baby i am 1cm dilated and 50 percent thinned out. i know it doesn't help you dilated but i would love some progress in thinning out my cervix some more! i will be 37 weeks monday. i was induced with my first 2 i really want to experience going into labor on my own.. I have hope this time around even though it's a little progress! thank you ladies :)