3/4 Ton rear brake line size...3/16 or 1/4???

[FLYNAVY30]

I thought I remembered reading somewhere that the rear lines are 1/4 inch? Im doing the rear disc conversion and while the supplied flexible brake hoses fit the new calipers just fine, I need to cut the factory hard line that went to the drums back about 3 inches and then flare it with a fitting that fits the new flex lines and want to make sure I get this right the first time since I'm sure this will be a PITA with the line still on the truck.

Thanks for the help!