Doing 2.5gl batches in 5gl buckets is the only way I brew for now. However, when I bulk age or secondary, I move it to a vessel with less headspace.
Drinking Pumpkin ale V2, Oaked Wee heavy, The Kaiser clone, Graff, Old Jubilation clone, Sour Cranberry Ale
Carbing/Aging Westy 12, Barleywine
In the bucket Peach Wit (FINALLY!)
On Deck Westy 12 (19X), Pumpkin Ale 2014, FBS clone, Port oaked amber, Old Rasputin Clone, 15% RIS