Mega-Recovery: roughly, the reign of Henry VII. This is a long transition period while the modern absolute state is being formed.
Mega-Awakening: the Renaissance (during the time it came to the North: we all know how much earlier it hit Italy, so hush, you art historians, hush) and the Reformation - think Mega-Blue and Mega-Red Awakenings here.
Mega-Unraveling: the period we call the Seventeenth Century - The Stuarts on the throne in England, the 30-years war on the Continent, that crazy geek Isaac Newton and his buddies of the Royal Society (think Silicon Valley today), sharp polarization between Puritans of various stripes and the established faiths, especially the Roman Catholic faith - the counter-Reformation-
Mega-Crisis: the Eighteenth Century (note: all Centuries are culturally, by popular definition, and not by the calendar!) "So, you say you want a revolution....!"
Mega-Recovery: the Nineteenth Century. Industrialism, Progress, so fat & happy & stable not even S&H could find a real mid-century Crisis on the continent or in England except the Franco-Prussian War and Paris Commune. Which as Fourth Turnings go was nasty enough, but quite brief. Victorian mores, parallel to "Look at me, I'm Sandra Dee, lousy with virginity...."
AND THE END! As we enter the new Mega-Saeculum --
Mega-Awakening: "The 20th Century". You can probably date it to the Missionary Awakening culturally - art, new religions and the revival of occultism, and all that - went mass-market with the old order died in the trenches of the Western Front. I keep saying, neither a Victorian nor an Elizabethan would have known a person of 1960 for their heirs without being horribly appalled. But they would have known each other well.
Mega-Unraveling: Starts with the Boom Awakening and we are still in it. See Seventeenth Century for parallels that strike me as being as obvious as the flood of colored lights and sales around the holidays. And I still consider the English Civil War to have been England's 4T. S&H were trying to keep England and the Colonies on the same timeline, and no, they were NOT.
Mega-Crisis: Let's let the dust of this 4T settle and look at the real, lasting problems we're stuck with and can't get around. My bet is on resource depletion and climate change. And what human beings have historically done when faced with resource depletion is that nations, states, and other people of power go to war to steal those of their neighbors in order to maintain the American/Roman/Mayan Way of Life. I expect the Crisis of 2100 - a Mega-Crisis-Era Crisis - to be a doozy. And the Recovery to be hard. And none of us will recognize the post-Crisis civilization. We would probably be totally appalled at it.