You have peaked my curiosity. Not just you Perry, but anyone here who is using these gap seals. Is or has it been your habit to use or not use your stabilizer trim during various segments of flight? For example, when you are down wind in the pattern and close the throttle. Do you ever move the trim before you touch the runway? Or do you just muscle the elevators to get the desired result?
I ask, because I have never found a lack of elevator authority in a Cub where I could point the issue to the gap between the two surfaces. A fixed stabilizer airplane, perhaps?
My PA-18-95 pattern and landing goes like this:
1. On downwind leg, even with the numbers, throttle back to 1500, 7 cranks to trim nose up and that yields ~60 mph with flaps at zero on my Cub (cause there ain't no flaps lol).
2. Base to final turn complete, roll one more crank nose up slowing to 50 which for me yields a steep stable approach and shortest landing roll, because energy management starts when you turn final. Any energy on final has to be spent in ground effect unless to spend it before you hit ground effect.
3. Begin to add back pressure just before crossing the fence to achieve 45 mph and keep adding back pressure to time it so that when I enter ground effect (half the length of the wingspan) I am at 35 mph and slowing and then just above touchdown pin the stick all the way back and it drops on a 3 point and rolls about 50-75 feet on the grass with 29" tires and bungees. It will seem weird to pin the stick back but if you are 35 mph or under it will not stall and fall and bounce, I promise. Don't pin the stick 15 feet up, I am talking about the point where you are like 2 feet above the runway and slow. Too fast and it will climb and fall. This is where practice is required to get the timing right.
Note: I usually push the carb heat in just before crossing the fence so I am ready to reject the landing if it is a short landing area. I also do that with 10,000 feet of runway to make it a habit.
4. If you want a wheelie, don't pin the stick back, nudge forward just before touch and hold it on the mains.
Note: On final if you sink, add a burst of throttle but leaving that in usually means landing long so just a burst. If you are high reduce throttle and leave it out. Don't change the attitude and don't dive.
IMO and as a CFI I teach that the steep stable approach is flown without lots of muscle on the controls on final, you should only adjust bank and rudder angle to compensate for cross wind, and adjust throttle for sink or too much height and the pitch picture (and resulting airspeed) stays the same. Otherwise you are fighting too many variables and the result is a long landing that misses your mark, or an unstable approach that ends in a poor landing.
I know this thread is about gap seals but adding them made this procedure work much smoother for me and more predictable on the elevator authority at flare.
Also, these speeds are approximate, especially below 50 mph because instruments vary, pitot angles force inaccuracy, etc. They are for reference only. The picture in the windshield i what matters and once you define it, it becomes more accurate than the instrument.
This has worked for me for 30 years on 2 cubs so it might work for you. When I fly HP airplanes, I disregard all this stuff and fly the V-Speeds, lol.