Hey @BTM_Pix,
you got the problem right.
I don't understand how your first solution is supposed to work? If I got you right you want to use this Keyboard Maestro App basically for remote controlling the Mac and run the tether app on it? The problem ist, that the tether app has no feature for video playback included. And transferring the file and playing it back afterwards just takes too much time.
But your solution with the Toshiba Air sounds really interesting, I'm just wondering if the transfer rate ist high enough.
But let's see, I have just ordered the W-04 card and will try it out.
Are you sure that it can be used as typical network drive? The only information I found so far is that it can be mounted as a WebDAV drive, but that should work as well I think.