How much sodium and potassium per day does the body need to stay healthy but not develop hypertension (assume daily exercise, cardio, resistance training)?

Contrary to what you might think from some websites, neither your sodium nor potassium intake will have any effect on your risk of hypertension. It's a myth. If you develop hypertension, you may be advised to limit sodium intake, but it's not the cause of high blood pressure. Assuming normal kidney function, just eat a balanced diet and you'll get appropriate amounts of both of them.