Gordon and Gary.
Experimentation is a powerful incentive to design. Notice though that the top pilots stick to some proven designs, or continue to build iterations of the same design. Modifying a small detail here and there as they strive for that perfect package. It's also important to note that design elements being close to optimum, will often lose to the more experienced pilots flying a less developed design. In other words practise and familiarity with the plane is usually better than most of the designing we can do. Over the years since this "sport" of competitive Cl Aerobatics began, many well seasoned experimentors/designers, have worked out the basic numbers to a point that most of what we can do now has already been done. The exception being the use of modern composits with stregnths and reliabilities undreamed of 50 years ago.
I'm not trying to discourage anyone, rather trying to encourage exploring paths that will reward us with the most bang for the time spent.
In the case of fully flying stabilators versus the standard style, and for now, we'll stick to 50-50 as far as proportions go, The amount of successes have not been good for the stunt event, compared to the performances with it for Combat. In Combat, the desire is for high speed, with the least amount of speed scrubbing DURING hI-G, high speed, turns. Normally there are several ways to get this type of performance. One of the best, in my opinion, is the combination that uses enough of a low wing loading with an airfoil that is rather stall resistant at the speeds used, combined with a tolerance for a further aft CG, while still maintaining control, and a fully flying stab, with the fulcrum near the leading edge of the stab-elevator.
Combat planes designed to this standard are fast enough in the level, but resist slowing during the turns and will literally "chew up" an opponent during manuevers. They have the reserve to out fly their opponents at the time when their opponents are at their worst, as far as flying ability goes. This is a great advantage, and the design is a large part of the equation. But this is not neccessarily the optimum setup for Stunt.
Most modern Stunters are designed to fly at about 55 mph, compared to well over 100 mph in combat. We need to optomise the hard turns within our speed envelope. Not only do we need to create the look of a square turn, but it must nuetralize, and lock in level flight effortlessy, or at least appear to do so.
I believe that the Flying stab, when we look at our requiements, isn't going to perform all our requirements as well as the normal stab-elevator will.
Partly, I believe we may actually benefit from a small increase in drag during maximum deflections, with slightly better stability during the turn. That extra drag acts in a similar fashion as the tails on an arrow, and I believe this helps in taming down wiggles at the rear during hard turns.
This should also help to create the look of a square turn, balancing the lift-drag from the wing-flaps, with drag-lift in the opposite direction at the tail-plane. Since the tail plane is smaller, when nuetralized, it should regain it's composure, Flying level, sooner than the wing and help snap and lock the plane into level flight.
So, how does having less percentage of elevator make this better? I believe that during the turn, the elevator may deploy dlightly higher to make the same force, but not substantially enough so that there's a huge increase in drag over the 50-50 setup. The advantage, to my mind, comes when the controls are nuetralized. Since more area is already at nuetral, the level seems to lock in , sort of a snap and lock. inhancing the look of, and actual quality, of the turn.
I was looking at several designs, and noticed that many of our modern designs use less than 50% area for the elevators.
Now, having said all the above, There are likely to be other opinions, and I know that there are those who have the training and ability better explain these theories than I. Hopefully they will add to this discussion.