With respect to the eyes, the 1998 edition of the Guinness Book of World Records claims that in 1878, an Architeuthis dux giant squid was found off Newfoundland that had eyes measuring a whopping 50 cm in diameter.
In the 1984 edition of the same book, there is some data on record giant squids. The 1878 specimen had a head/body 6.09 m long and tentacles 10.66 m long; it probably weighed around two metric tonnes. In 1887 a squid of a different species, Architeuthis longimanus (longimanus means long-handed), was washed on the shore at Lyall Bay, New Zealand. Its head/body measured only a measly 2.02 metres, yet the tentacles where 14.93 metres long!
In writeups beforehand it has been mentioned that giant squids eat whales. I don't think this is a scientific fact. It is known that giant squids fight with sperm whales, in self-defence probably, since their tentacles are often found in sperm whale stomachs, but it's unlikely that they really feed on whales.