I've come to the conclusion that if you want to always be safe and have a *guarantee* of not crashing beyond the runway due to an engine failure up to the point of Vyse when one can safely climb away you need at least 1300m of runway.
I've never had cause to abort a take-off/climbout at Vyse in hundreds of Twin Comanche departures, but I think you'd need a lot more than 1300 m. I'd want more like 1800 m.