I have no idea where I am going to top out, but I am going to take the route of continual exposure means McGalleon ages faster, with the shields up, the process slows.  I know he aged twenty years pretty quick, but I feel where he was in the ship and w/o shields, it is well in the realms of possibility.  Besides, I dont mind being the lab rat or template as it were to try and figure this out medically  ^.^