Firstly, A boat setup to have a giant roost will not be as quick as it could be if it were set up normally. What prop to use depends on a lot of different factors. What hull, how big, what motor etc etc.
From the looks of it you plan on using an 11400Kv motor. This Kv rating is waaaay to high (as in prop RPM over 100K per min). You will be better of with something around the 4000Kv mark.
People will need a lot more info on your plans to give the best advice.