I too am confused as to what your issue is. Do you plan on doing the inner circle like reverse applique? (IOW you are turning under the sunflower and appliqueing that to a smaller background square?) What issues are you having? I think either way, whether you applique a small circle to the center or reverse applique the block to a small background square, lots of starch and glue will be your friend.
Your blocks are beautiful.
Edited to add, you may want to look into the technique known as applipiecing. There are some you tube videos out there. Sharon Schambers calls it Piecelaque and Caroly Bryer Fallert calls it applipiecing. I think it might help you. If you subscribe to The Quilt Show both techniques are shown there.
Last edited by feline fanatic; 10-11-2019 at 07:00 AM.