The
Rohloff site has a lot of info which you can search for answers to your questions.
Try starting at this
spoke length page.
The Rohloff manual has a lot of spoke length information on pages 42-44.
My Rohloff hub is laced into Sun Rhyno 26" rims with spokes of length 240mm, my front wheel has a Schmidt SON dynohub and that is laced with spokes of around 260mm.
I hope this helps.