Don't really know about the stroke length, but it can't be too much. I just hooked mine back up after 25 years of being in a box, out of the way. Decided I could use it for some "old time type" engraving to play around with again.
Not sure of the stroke length but the Ngraver is capable of master level work in the right hands. However. I would go for the Lindsay Artisan if your trying to save money.