We mostly have pails for the smallest containers, but have some gallon or quarts for some products.
The Havoline ATF being one. Delo MD-3 another. Delo Syn ATF is pails. Pail isn't a huge deal, truck transmission holds around 5 gallons, just would have to transmissionfer to gallon jugs to pour in the transmission or use a bucket pump.
I ended up reusing what I drained from the stock pan and I had ~2 gallons of Mercon V in stock so had enough to fill the transmission. Should be good for a while unless it decides to leak or come apart.