Ok, I'm not 100% familiar with Knossos, so I can't give a quick fix, but I can tell you why this is happening:
It's because the HUD elements are always drawn at their base resolution, in other words; they don't resize.
It can be made to resize with a setting, but it's not a normal game setting that you can access, the actual file that defines the HUD itself has to be modded.
I don't know where Knossos puts the mod/game files, so someone else will have to post instructions on what directory to go to and/or create, but once you have a .TBM file (opened with notepad) called "mv_root-hdg.tbm" there should be a line of code that says: "$Scale Gauges: NO" replace the NO with a YES and that should make the HUD much bigger.
Please Note: Everything I just typed is useless unless someone with knowledge on how to make mods using Knossos posts in this thread with a specific explanation of what directory to find and where to create/edit the needed file.