Re:
The outer’s lengths surely depend on what bars/stem/spacer you are using and , where your levers/shifters are bolted on the bars etc
Unless you are doing a perfectly accurate factory build why is it relevant? If you are doing such a build then get some pics up as I’d be interested as Zaskars are my favourite retro.
Just make them the length that looks right , allows them bars to turn and it’s routed correctly.