I know different numbers were used and tossed around, but I was never clear about this. How old were the "Final Five," or the original humaniform survivors of the first Earth that taught the Cylons how to make other humaniform Cylons?
The Final Five were originally born about 2000 years BCH (Before Cylon Holocaust), plus or minus a lifetime. Their current biological age is the same as their apparent age due to time dilation while they traveled at relativistic velocities and the time they spent while "boxed" by Cavil. Tigh is about 70, biologically. The others are of course younger.
Based on the series timeline below, they aged about 10 years after they arrived at the colonies and met the local Cylons. They must have aged only very slightly during their stopover at Kobol. So subtract 10 years from their current (i.e. Miniseries) apparent ages to arrive at their ages when they met the Cylons.
ca. 2,000 years BCH: Samuel Anders, Tory Foster, Ellen Tigh, Saul Tigh, and Galen Tyrol, later collectively known as the "Final Five," are born on Earth.
2,000 years to 52 years BCH: The Final Five arrive at Kobol, finding the planet abandoned. They continue on in pursuit of the twelve tribes, heading toward the colonies.
52 years BCH: First Cylon War starts.
40 years BCH: The Final Five arrive in the Twelve Colonies in the waning days of the war. The Five meet the local Cylons and negotiate an end to the war. They will give the Cylons biological bodies complete with resurrection technology if the Cylons agree to end the war.
ca. 30 BCH: The Final Five are murdered by Cavil and their consciousnesses are boxed. Saul Tigh is resurrected and introduced to the colonies as a military officer with false history of fighting in the war.
69 years BCH: Saul Tigh supposedly born (defined by deleted scene in "Valley of Darkness" concerning the Brenik). This is actually a fabrication by John Cavil.