used r-22 worth it?

rotor-heads,

I'm a private pilot with about 100 hrs fixed wing, and about 15 hrs in
the R-22 years ago. Sometimes I think about finishing that helicopter
add-on that I started and maybe build a significant number of hours.
I've seen used R-22s, within 300 hrs of refurbishment selling for
40-50k. Assuming I bought one of these and put 300 hours on it without
destroying it or getting myself killed, how much could I sell the hulk
back to robinson for refurbishment? And when you factor in
maintenance, hangar fees, and insurance are you better off just paying
the rental rate at a school, which approaches $200/hr from what I've
seen?

Also these little guys don't have much rotor inertia, and you have like
one second to drop the collective or die in the event of a power
failure, right? In the Army (I was not an aviator, just a cadet at
CTLT) I remember seeing a pilot momentarily moving his left hand to the
cyclic so he could take notes on his knee-board with his right. That
would probably not be advisable in an r-22.

Thanks,

Dave