There's only one paper on Doswellia. The original. And the images on
Palaeos.com are from that source.
Doswellia nests at the base of the Choristodera and Cerritosaurus is the
first outgroup taxon. One of the Younginas is the next outgroup.
If you don't even find the crown-group of Diapsida in your analysis, I can't
get rid of the feeling that you don't have enough characters for your huge
number of taxa. What about the middle ear?