Hi again,
I am puzzled by your experience, so I downloaded the HUD gauge and installed it in the default Cessna 172. I tried three different optons, as per the attached images and the panel.cfg excerpts below:
Image1 - default centre position as per Bob Kellogg's installation instructions
//--------------------------------------------------------
[Window06]
Background_color=0,0,0
size_mm=202,168
window_size_ratio=1.000
position=7
visible=0
ident=304
window_size= 0.316, 0.350
window_pos= 0.330, 0.020
gauge00=gaHud29!hud2A9, 0,0,200,166
//--------------------------------------------------------
Image2 - moved the HUD over to the left
//--------------------------------------------------------
[Window06]
Background_color=0,0,0
size_mm=202,168
window_size_ratio=1.000
position=7
visible=0
ident=304
window_size= 0.316, 0.350
window_pos= 0.050, 0.020
gauge00=gaHud29!hud2A9, 0,0,200,166
//--------------------------------------------------------
Image2 - moved left and downward
//--------------------------------------------------------
[Window06]
Background_color=0,0,0
size_mm=202,168
window_size_ratio=1.000
position=7
visible=0
ident=304
window_size= 0.316, 0.350
window_pos= 0.050, 0.390
gauge00=gaHud29!hud2A9, 0,0,200,166
//--------------------------------------------------------
As you can see the HUD is easily moved to different positions on my system. Sorry I have no idea why it is not working for you.