HELP! Pitching soon!

I posted several days ago saying that I planned to split an oatmeal stout batch and pitch each half (2.5 gals each) with two different yeasts (one with Pacman from a Shakespeare Stout bottle, one with Irish 1084. I'm in the middle of my boil right now, and things are going great, but I'm starting to get worried about fermenting these brews in 6 gallon buckets, which is all I have. Is there too much space between the top of the beer and the top of the bucket? Will the added oxygen from increased empty space in the bucket have any effect on my final product?

Thanks for your help!

Initial fermentation should take care of any oxygen in the head space and replace it with CO2. I'm certainly no expert but I think you will be fine.

ditto
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