The hoped-for archival evidence on a Vickers dive-bombing sight

Which theory would you most like to find an archival smoking gun for?

Decisive evidence about the Vickers dive-bombing sight is the preferred research prospect.

Decisive archival evidence about the Vickers dive-bombing sight is a personal research priority. Such a discovery could change the historical discussion of dive bombing. The hoped-for document remains a research prospect, and the sight's capabilities are left unspecified.