Hi Neil
I'm no expert but..
"You can bend the crank with a windy gun!!" Blinkin' 'eck! How much torque does a windy gun deliver? I'd expect my arms to be ripped off before the crank bent - (but what do I know?)
ps. Nice to see you eventually got yourself an 851/888. If I remember right, you were once after my 888 Strada!
Steve