Thank you for your question. My recommendation is to avoid mixing these products by volume and instead mix them by parts per million using an inexpensive EC meter. These meters can be purchased online for less than $15 and are reliable enough for home hydroponics. 

As far as what concentrations to use, for anything which is consumed primarily for its leaves, I recommend mixing the Calcium Nitrate 15-0-0 to a concentration of 200 ppm (as measured on the meter) into your water. After this product has thoroughly dissolved, in a separate container mix your Magnesium Sulfate to 200 ppm. Once thoroughly dissolved, you can then combine the solutions together to create your final nutrient solution. Attempting to mix both nutrient sources together may result in precipitation, which you want to avoid.

Focusing on keeping your nutrient solution under 400 ppm and at a pH between 5.5-6.5 will do more good than trying to tweak individual elemental concentrations of nitrogen, phosphorous, and potassium. 

There are some crop-specific recommendations out there, but they assume commercial-level environmental conditions to include light intensities that are not common to home practitioners.