It's our home ground. You haven't played there since Rd 18. To say that 'it won't be a factor'.. I think you might be wrong there. It does play a part. How do you give it a %. I dunno.
Look at Anfield man.. no crowds.. they lost a lot of games.. crowds back.. 21-22.. didn't lose a game.
You're right in proabably being a factor, albeit a small one. But also quite a few differences.
It is your 'home' ground, but it's also a few other clubs home ground too unlike Liverpool/Anfield.
Given other clubs play home games there (including us), you don't have a monopoly over it. This is our 7th game there this year; we'll be pretty familiar with the ground. This is far less daunting than travelling to a ground for a one-off game.
It's also a final at a convenient time for Geelong fans. Which means you won't have a 90/10 mix of the crowd; the crowd will be relatively neutral. This also nullifies quite a bit of any perceived advantage.