I replaced all the rubber in the Canon this afternoon, with the exception of the tire that drives the idler gear. I started taking stuff apart and became very reluctant to proceed any further - the tire looked and felt okay, so I left well enough alone. She seems to work fine now, just have to thoroughly clean the head. The Philips has gone to the great round file in the sky - didn't think replacing the reel sensors was a cost effective option, especially since the machine has been heavily used.
Thanks again for all you advice guys