I have been doing quite a bit of research into the Johann Gottlob line, but like you, I cannot trace the family to Dresden. Any information you find that you will be willing to share will be greatly appreciated. I do know that Johann and his wife, Johanna Christina, left Germany and went to England, June 18, 1815; and he was naturalized on October 19, 1850. I don't know if you had that information or not. Since you are a member of Ancestry.com, I suggest that you check my tree (if you have not done so), the Waetzig/Weil Tree, since I have quite a bit of information on it.
My line comes through Charles Aldophus, to George Arnold, to Arthur C, To Francis W.