Ah, but the tailplane carries a variable "load" depending on the CG location and the pitching moment of the airfoil.

Cruncher, if you can locate the CG and select a wing airfoil such that the pitching moment and the "stability lift" that the tail needs to generate is at or darn close to zero for a lift coefficient then the tail will be only producing the profile drag. Selecting a good, thin, known performing high speed airfoil will go a huge way towards minimizing the tailplane's drag.

There was an old DOS based program called "Sailplane Design" many years ago written by David Fraser. That program not only provided the wing's lift coefficients for a range of speeds but also the tails lift coefficient. It was very interesting to see this stuff in action. It didin't take me long to realise that for my optimum speed for moving around the sky I wanted a CG location that generated the least tailplane drag at the best L/D speed.