Either Dubro HD ball links are fine. I've used the straight wire HD extensions without troubles... (22 ga I think) Bigger is "better" but also heavier... your call...

I wuold definitely go with the SmartFly 6 volt regulator w/ failsafe switch on the receiver... lightweight and well thougth out.

An MPI HD switch w/charge jack is fine for ignition... (or even a regular switch harness but i liek the easy access to charge)