Query in PCB Filter panel,
IsVia AND NOT SolderMaskTentingBottom AND (AsMils(ViaDiameter) >= 40)
The above method helps you generate the query, a good way to get familiar with the scheme.
And yeah, PCB List is best way to get their properties. Net, X1, Y1, etc.
Alternately, tag them as Assembly Testpoint - Bottom and get the Testpoint Report in the OutJob or whatever. This can also be assigned automatically (by rule) from the Testpoint Manager dialog.
Tim