Ali here.
Funny I have never noticed the wing fences on any of the 3 Hawks that I have built and flown to date. My prototype model that I flew (T-45 colors) never had them fitted and I am sure if you have seen the videos you will have no doubt that the slow speed handling was perfectly acceptable, if not darn amazing. My latest model (Red Arrows) Scheme has worked out a little heavier due to a heavier power plant but as Henry confirms flys very slowly. I really don't think you could ask for any more slow speed stability from a jet but I am going to try some up aileron deflection to see what change I get. Then I might fir the wing strakes.
I am really reluctant to fit these as they look to me as a part that is just waiting to get knocked off and with the on the wing becomes a pain to transport.
As for tail plane. Again all of the hawks that I have built/ flown have all been with on JR 8511 on the stab, and over 22 hours of flying with no trouble. Having said this I did recently update my red arrows hawk for two 8511's on the stab and found that it did give the model a more solid feel on the elevator stick at all speeds.
As far as elevator response with motors like the Titan and suchlike. I really think customers will be on their own on this, as the model was never intended for such large power output turbines, and we strongly suggest against overpowering the hawk in such a way. The model is perfectly capable of withstanding flight loads in the envelope that it was designed for. Why would you want to know how the model performs well outside of these. I am sure I can get any model out there, designed and sold by any manufacturer and overstressed the airframe with to large an engine or irresponsible flying thus causing it to break.
As far as balancing. Again none of the hawks that I have built or flown have had a mass balanced tail. I have contemplated it but I just cant bring myself to add all that weight to the tail, knowing I will have to compensate it at the front. Once again I have never come across any issues with tail control at low or high speed.