Some Grand Final Stats, just looking at the past 10 seasons.
The past 6 GF's have been won by the team that finished higher on the ladder. (Sydney)
The 4 GF's before that were won by the team that finished lower on the ladder. (Brisbane)
6 of the past 10 GF's the margin has been 46+. The highest margin is 89.
Those 6 GF's had an average margin of 67. The other 4 GF's had an average margin of 16.
The past 10 GF's the average margin is 46. This fits pretty evenly with the average margin of every GF ever played.
In 4 of the past 10 GF's the losing team has recorded their biggest losing margin of the season. (Sydney -112, Brisbane -54)
In 4 of the 6 remaining GF's the losing team recorded their 2nd biggest losing margin of the season. (Sydney -5, Brisbane -26)
Obviously we can say, 8 of the past 10 GF's the losing team has recorded their biggest or 2nd biggest losing margin for the season.
In 7 of the past 10 GF's the team that had the lowest 2nd biggest losing margin for their season won the GF. (Sydney -5)
In the other 3 there was one tie, and the team with highest 2nd biggest losing margin won twice.
Looking at %'s, For and Against. The team with highest %, and the highest For total have won 5 out of past 10, so evenly split.
However, the team with lowest Against total for the season has won 8 of the past 10 GF's (Brisbane 1,747 , Sydney 1,769)
I'm going to say Brisbane by 49, and McCluggage for the Norm Smith.