electability arguments are always but always bullshit that is trying to snow you. vote--and advocate as vigorously as you can for--your preference in the primary, vote against the greater evil in the general. anybody who presents a different option takes you for a rube.
you should vote for the candidate that you think will do the best job in office for their constituents and not try to do some pool-trick bankshot based on ads that haven't been cut yet and perceptions of how median voters will react