*UPDATE*
Proportions seem right with these settings:
texture 2462 { pal 0 { file "hires/tweaks/hud/hudfin1920.png" orig_sizex 370 orig_sizey 34 artquality } }
However, the background tile is showing, even with statusbar scaling at 100%. Not sure if extending the whole thing on both sides even further would do the trick.