Not sure you need that big hunk of aluminum hanging off your transom. Dual rudders do not do anything to improve performance - they will lessen it if anything. A simple strut and offset rudder is more than adequate. But if you like the MS dual then the MS dual it is.

You dont need a titanium pushrod set as mentioned above. You dont need it and may break it easier than a steel or SS rod of same size.

I have not heard what motor your running so cant say exactly what prop to use. For 99% of gas motors a Prather 270 or 275 will be a great place to start. This is considered the best all round prop