Maybe, try to write temporarily acaddoc.lsp with lines that have to be automated when each *.dwg is opened, and try this c:test function >>>
here<<<
Sure, ObjectDBX is the fastest, but I suggest this one, because it's simple and you don't have restrictions like with ODBX (no commands, no setting of sys variables, ... ). And beside that with my proposal you can save it as any file type of *.dwg that has thumbnail for previewing *.dwg when browsing...