Hello..it would have helped me to suggest you better if you had attached the usg report...since you are mentioning that you have significant post void urine..we need to evaluate you for the cause of it..its better you consult a urologist to find out the cause of incontinence.. Whether it is stress incontinence or something else

IS this problem more at night or every time? Are you married? Is any sensation of burning or itching present while urinating? Have you done your blood sugar test if not then do it both PP and fasting. Provide me above information. Some time due to over sensitive or over active bladder are also can cause.