I see that quiz has only been played a few times, so I would wait a bit to see if the percentage correct changes after a few weeks. Especially when a quiz is on a fairly obscure topic, the difficulty ratings swing quite drastically at first.
Often, some thoughtful reworking of the incorrect answer options is a good way to make it easier for players to figure out the correct answer, even if they don't really know it. Rewording of the question also helps sometimes, as you can incorporate clues.
We only ask that if you make any change to a question that is more substantial than a minor spelling-type fix, you resubmit the quiz, so an editor can check it. Include a note, either with the quiz, or directly to the editor who originally put the quiz online, (or another editor in that category) explaining what you have done.
As for the submission rate, once you have one quiz online, you can submit the next right away. Spend the waiting time working on your offline quiz, making sure it is free from errors, etc. We do ask you to get one quiz on before submitting another, rather than having a whole batch of quizzes 'in rotation'. Often the editorial comments for one quiz will apply to others, so it is much better to address the issues on the first quiz, and learn from your mistakes, to avoid the same problem in subsequent quizzes. Most editors will not accept a quiz if you have another quiz with outstanding rejection notes.
Funtrivia editor agony