Command line control of playback position and size

[summat]

I'm pretty new to VLC (okay, it's been the stalwart for many years for generic playback, but now I have a specific goal in mind).

Background: Running Windows 10 and Windows 8. Currently using VLC 2.2.4

What I want to do is launch VLC from a command line to play back a video behind the active window. I can control the environment such that only one window is on screen - so one option is to play back as the wall-paper. Also, I want to be able to specify the X,Y as well as Width and Height, and - for preference - have the video scale to match that given Width/Height. I need to be able to reconfigure the window - possibly by quitting the current VLC task and restarting (though if run-time reconfiguration is supported then great).

So far I've been experimenting with the following options:

--video-wallpaper : to force the render to the wallpaper, and therefore behind any window.
--no-autoscale : to stop the playback scaling to full screen size
--no-fullscreen : not sure if I need this with --no-autoscale - quick experiment suggests not
--I dummy : just to get the minimal interface, plan to have this hidden
-- width=200 -- height=100 : THESE DON'T WORK AS I EXPECT
--video-x=10 --video-y=10 : THESE DON'T WORK AS I EXPECT

I've noticed the --align command line option, which places the video centre/left/top etc - but there seems no way to turn "align" off - I don't know if that is overriding the playback position (--align=x appears to work as documented, but I need to be free to specify the playback position so need to override the align settting).

width/height as well as --scale have no discernable effect on my command line behaviour.

I'm sure that I'm missing something obvious here, but the problem is, as a newbie, the vast number of options are making trial and error more error.

Can anyone suggest a solution to what I'm trying to achieve - and if this is a command-line issue, just what options I need to specify.

Cheers, in advance,

Mike