If I want to design an aircraft that can fly with high speed while loaded, which tail type should I choose.
The mission is to design an aircraft that can move a certain distance with high speed while carrying certain load.
By Staff Sgt. Bennie J. Davis III [Public domain], via Wikimedia Commons
Split brake-rudders will do the trick.
You can also try and beat NASA and Boeing to the Active Flow Control tails.
Or just settle for a T-tail.
The horizontal tail plate effectively increases the aspect ratio of the fin by virtue of the 'end plate' effect. The T-tail configuration is especially popular on gliders.
(Flight 1977—PDF) Early Boeing 757/767 designs featured T-tails to reduce drag.