I know a bit of the story on Asa and there is a Gent in CO, Waddy Colvert. He is descended from Asa. Have you been in contact with him?
A fellow Calvert researcher looked into Asa etc and posted some on this list. It might behoove you to post a query with a family descent of what you know at the discussion list which accompanies the FT/DNA Calvert Surname project at Yahoo groups. If you know a Calvert of direct descent with this surname, who descends in Asa's line, then that would be the second sample garnered for this line.
At any rate, here are the websites that may assist you:
This is a discussion list of family researchers that was started to accompany the project. I suggest that you post a query there and provide a 'brief', chart or report of how you descend from Asa and see if anyone can help.
D... respond to email address firstname.lastname@example.org if you choose...