Back to RV limitations:
I have seen both 2600 and 2700 as the total number of RV6's built. There has never been a structural break up of a built to plans RV6.
There have been several RV7 fatal structure failures. The one near Atlantic City was non builder who was trying to learn aileron rolls. Some of those attempts were observed from a friend flying nearby. Repeated split S exits from inverted flight. On the accident flight the other airplane was not present. Ground radar indicated excessive speeds. The final report identifies the rudder as the first part to fail.
When I was instructing aerobatics I would always start a briefing by asking the trainee what they had been flying and what their goals were. A gentleman, [perhaps late 60's, had tried to teach himself rolls in his RV6. He admitted to stopping the roll inverted, pulling thru to exit, probably did not reduce power until almost too late. Almost 300 m/h and an unknown g load. It is my opinion after reading RV7 accident reports that doing that in an RV7 will be fatal.
The irony of that I introduced people to aerobatics in the Pitts S2B as follows.
This was the first aerobatic maneuver.
Some were non pilots.
Roll the airplane from 30 degree bank in one direction to 30 degree bank in the other diferction
Keep increasing the bank angle to at least 60 degrees. A touch of coordinated rudder.
Next from cruise speed or slightly above pull the nose up at least 20 degrees above the horizon.
Repeat several times and then start releasing the stick as soon as the climb angle is established.
Now establish the climb, immediately release the stick and put your finger on the right side of the stick and push with your finger.
Success rate of well over 90% on first attempt even for non pilots. About 15 minutes learn the basics of aileron rolls in the Pitts. This was the first aerobatic maneuver. I never demonstrated it. Simply talked the trainee thru it. Then proceed to hands on the stick rolls and then spins. Any sign of airsickness we landed. Two years of one day off a month. never had anyone puke in the airplane. A couple of events just after getting out.
I had exchanged some emails with the Atlantic City pilot but never discussed aerobatics.