Very happy to hear of your safe recovery on the dead stick. You are certainly gutsier than I to intentionally snap roll a warbird, but it's very reassuring to hear that this airframe sounds very dynamically stable, but not so much so as to be a slushy acrobat..."snaps quick, but stops as soon as you release the controls." That's pretty cool
Just to clarify that I am thinking of the same manuver that you are executing; for me a "snap roll" is entered from straight and level , 2/3-3/4 throttle. Add just a touch of up and then firewall the throttle simultaneously adding full left rudder(left stick in upper left corner) accompanied by full left aileron and full up(right stick at bottom left corner). Prop torque adds to the effect in a left snap and diminishes a right snap. I'm comfortable with this on my ultimate bipe or sportster 40(the only planes I trust not to go into a death spin). Tried it with the J3 cub once and it sort of just fell over is the only way to describe it...quite unimpressive and upon neutralising the controls it wound up in a level shallow descent; I guess that's a Cub though[&:]