wobbles to rickety, too few adjustment possibilities

Well, I use it because I did not again want to buy a new,
but the intense games wobbles the frame like a cow's tail!
Tried, with documents (glued) to compensate it, though was better
but the thing is just too rickety.
Moreover, it is too strenuous adjustable in my opinion, with the tricky raus and Reingeziehe of the
Metal pin at the same time holding the frame - one would need 3 arms - is not simple?
The 5 height adjustment eyelets me personally too little, would be just in the middle Breich
another hole have been useful (Playing Sitting Down), as is the existing
Setting either just too high, or too low.
Conclusion: Not really bad - but certainly also not really good ....