I'd probably lose a day trying to calculate it.
I think guess the minute of the first goal might be easiest!
I used to run a competition at work with 10 games, predict the score. 3 points correct score, 1 point correct result. Almost always gave clear winner(s) and a good spread of scores. Tiebreaker was guess minute of the goal from one of the games.
I'm happy to arrange and score. Could get a template uploaded this evening and get entries sent to me before Saturday.
Results should be available either Sunday or Monday.