I have the CG way back (at the limit suggested by Sig the the manual) on my LT-40, and the throws are very high. It will do a rudder-elevator snap at about 1/4 throttle. If I snap the plan, then hold the rudder-elevator inputs, and the throttle at about 1/4, it will enter a spin. I can then reduce the throttle to idle and it will stay in the spin with just the rudder-elevator input. It looks very much like a true spin, not a spiral. I must enter the spin starting with a snap from level flight or it won't spin.

In the LT-40 manual, Sig say that it is capable of snaps and spins if the CG is back at 33%, where I have mine.

Even with the CG back at this position, it is still very stable. I expect it can be moved back further such that a spin can be entered from level flight, with the throttle at idle, as is normally done with an aerobatic type plane.... but I have not yet tried.

I'm not sure about a flat spin just yet.

Other LT-40 I've flown, with their CG further forward, are indeed so stable that they will do little more than a spiral dive.