Some helpful info:
Cravat variations
Waistcoat
The waistcoat image comes by way of the Oregon Regency Society. Who knew there was an Oregon Regency Society?

Bonus hot guy - "Mr. Darcy" models a man's Regency period shirt - which did not unbutton all the way down, as you can see.
This information will all be very helpful for the next DC installment.