It is still being flown as a powered ultralight and its spin behavior has been thoroughly explored. It likes to enter a spin with little warning and spin steeply no matter what the control configuration, according to pilots I recently interviewed. On the other hand, the Icarus V, the Easy Riser and the Fledgling were fairly spin resistant, although they would spin nicely when provoked. There are three additional design factors besides twist that affect spin characteristics. They are sweep, taper and airfoil distribution.
Taper promotes spins because it increases the local loading out at the tips.
In effect, if the chord of a wing gets smaller at the tips, the airfoil is working harder. For this reason, the airfoil can also make a difference. A thicker airfoil in relation to the chord length at the tips helps reduce spin susceptibility. Sweep is important for pitch stability in a flying wing. Taper is useful for performance.