There isn't that much fluid that will come out in the first place, perhaps a cup at most, just turn it up as soon as you can, you won't get any fluid leaking out of the front of the transmission once it is out (at least I never have), unless you tip the transmission forward after the converter is out. The rear of the transmission, after the drive shaft is pulled out, usually will leak, I usually tie/tape a plastic bag around the end so I can drain it later. If you drop the oil pan and control the fluid mess before disconnecting torque converter and pulling drive shaft, that helps a whole lot, and lightens it a little bit, too. Oh, and the transmission fluid lines will leak, too, a rubber fuel line and hose clams to connect the two together helps.