Sunroof drain line Diameter ?

Guys
Need to replace a portion of the rear sunroof drain line for a 71
One side exiting at the gutter is fine the other is rusty and end as it exits to the gutter. I need to cut back some metal to get at it .
But definitely will need a small section of metal tube to replace the end and re detail the end condition at the body/gutter
Looks like either 10 or 12mm OD
Thanks for assistance
Frank

Rear tube takes a hose that is ID 14,00 BTW, front is ID 10,00

Thanks for info....... but am needing the metal tube coming from the back of the roof and leading down to the gutter drain.
It runs inside the sheetmetal enclosure at edge of flange for rear glass

Anyone else ?
Thanks for assistance
Frank