TLDR: It doesn't matter that much, a couple feet should be fine. I just pull my an EVA barrier serving tube to use for my closed transfer when needed.
Long version:
That seems reasonable. In my limited experience, I transfer with a VERY modest pressure differential. So if I spund up to 30psi, then cold crash it should end up at around 12psi...
Then I purge the receiving keg to 12psi and check the spunding gauge on the kegmenter.
Then I pressurize the kegmenter to 13psi, and attach the jumper to both.
Beer may flow modestly but often requires me increasing the pressure to get flow.