The painful part is when the engine tries to rip the pull cord out of your hand when you try to start it. No, I doubt very much that the small mass of a clutch drum rotating so near the center of mass of the crankshaft would help much. I speak from personal experience; tore the skin off two of my fingers, put a heck of a bruise on my right thigh, very close to my precious dingleberrys and left me with memories I wouldn't want anybody else to have to re-live. Been there, done that and I ain't a' goin' back!
As I'm sure you know, a flywheel is all about storing kinetic energy, something of a high mass and a small diameter can work, but if the diameter is larger, the circumference of the flywheel travels at a higher feet per second rate, storing much more kinetic energy than something of the same mass traveling closer to the center on a smaller diameter flywheel. If a large portion of the mass is located near the outer circumference, the effect is amplified. In other words, yes, a clutch drum is fairly heavy and if it had a diameter of say 6 or seven inches would probably be more than adequate, but I have my doubts if your standard size clutch would provide the necessary rotating mass.
I dunno, it might not be an issue and the only way to know for sure is to try it, but I would recommend when starting the engine for the first time, the user wear a good heavy pair of leather gloves and stand off to one side just in case. I'm sorry for dragging this thread off topic.