6 foot 8 inches
No human skeletons were ever discovered that were 8 foot tall. Largest skeletons discovered were in China, being 6 foot 8 inches. While this does not sound tall at all, from a historic point of view, an almost 7 foot men would tower over his 5 feet counterpart back in the days.
It's interesting your evidence would be so easy to debunk
"With regard to the 'giants' of Santa Catalina Island," Johnson wrote, "these reports are apocryphal, as far as I have been able to determine. For example, there’s a historic photo of Glidden in the background and the burial in the foreground, merely creating an illusion that the skeleton is somehow a giant."