Spec of the fuel hose for twin carbs on a KR

Hi all, hoping someone can help with details of the fuel hose I need (my Golf is in storage and I can't get to it easily to measure up)-

What length of fuel hose is needed for twin carbs on a KR in a MK1? And what internal/external diameter? 

I know that mine had the reassuring addition of electrical tape around the hose at the first carb and I'd like to upgrade everything to a proper, secure, fire safe set up.

Many thanks for any advice and dimensions you can share!