Ken is correct. I couldn't bring up the tail link he mentioned but the photo of the BVM kit seems to put it at around the 25% mac of the tail.

What you need out of the horizontal tail is both static and dynamic stability about the pivot and small actuator loads.

Static stability is obtained by putting the pivot at the center of the tail load - the neutral point of the tail. That is 25%.

Dynamic stability which is resistance to flutter would need the tail loads biased a little aft of the pivot point (pretty sure I am remembering this correctly, it is morning and I have a headache).

Actuator loads require putting the pivot at the center of the tail load.

It would be hard to go wrong with something 23 to 25% of the tail mac.

50% mac would put a tremendous load on the actuator as would 10%.

I went to the Sullivan, MO Jet Flyin last Saturday. I was very impressed with the state of the art in jet modeling. Beautiful airplanes with beautiful workmanship. Flawless flying and the equipment worked all of the time. I'll have photos on the internet in a few days and will let you folks know where to look.