Everything I'm going to expose is in accordance with my sense of justice. The rules are made by you. I will speak the way I would like it to be. So consider this as a suggestion for future situations.
I don't think it's fair to consider that game null, due to the mistake of a third person. Your fault was direct and commissive, because you were the host. Adnan and I act with omission and inattention. But the obligation to put the correct scheme belongs to the host. Imagine the work it would be, every time someone creates a game, you go out looking at all the scheme settings. The host is responsible for selecting the correct scheme etc.
If I had been the host, I wouldn't be having this debate. I would take the blame, and the opponent would deserve a tech win for my mistake in selecting the correct scheme (not a rematch). If Adnan had made the mistake, the fairest would be for me to have the victory.
An individual cannot suffer the consequences of a third person error. Also, we must take into account that this affects the psychological of the player, who has to "win a second time" and endure the frustration of having your victory canceled and time wasted.
But then we can ask: if Adnan was not responsible for the error, just as me, he cannot be harmed by something he has not caused. That's why Adnan's opinion about it is important. Did he think he lost because he had 7 worms instead of 8? Does he think this error interfered with the result of the match?