Tranny line size

I am getting ready to order a temp sending manifold for my tranny temp guage and need to know what size the lines are coming out of the tranny so I can get the right one. Im going to use the manifold for now until I get around to making a deeper tranny pan and then I will move the temp sending unti to the pan. This is what I am looking at for now, do I need the 3/8 in. O.D. tubing manifold or the 5/16 in. O.D. tubing manifold? This will go in the "hot" line before the tranny cooler.

http://store.summitracing.com/defau...ifold&Ntk=KeywordSearch&N=110&PartSearchFlag=

you can get a setup like that from B&M for like $65 IRRC. it has everything you need, gauge, wires, hardware, etc - and has two different T's for different line sizes. theres a tech article on jeepin.com about it.