I have always had RTR boats and then upgraded them for racing but find this process of more or less starting from scratch brings questions
I never had to think about before.

Basically I have the Delta Force DF-45 hull and am planning to use a TP4070 1650KV 5D motor with a Swordfish 240A HV ESC. I plan on running
6S at first and perhaps step up later. All the stern hardware is hung - the stuffing tube is in and lined up and I am about to glue in the motor/servo mount.
I will be using a .187 shaft.

Questions - What prop would make sense to start with on this - perhaps a 447 or a 450? - I usually use Octura props.
What is the difference between a tapered rudder and a straight one other than looks ? I have the speedmaster dual
pickup ros-spdr-011a with a five inch setback - the T block is mounted. (this is a tapered rudder)
This ESC requires a battery pack or a UBEC to run the receiver another first for me. What seems better for
this job? I have a unit that holds 4 AA batts and could put a switch on it. Or I can buy a UBEC which is hooked directly to
the ESC input leads? - or I believe some guys are using small lipo batteries???

I would welcome any help with the above questions and /or with the basic setup that I have outlined above although
changing that may be difficult as the money has already been spent. Thanks for any ideas/suggestions you may have.