This mod allows the player to choose the horn/debris size for Venom Snake, with and without the bandanna.

Install (or place) the modded data in the UNPAKCED file path of 'chunk0' shown bellow:

(EXAMPLE)
C:\Documents\QAR-GZSTOOLS\chunk0\Assets\tpp\pack\player\fova

then repack and place the newly created chunk0 in the
main game folder called 'master':

C:\Program Files (x86)\Steam\steamapps\common\MGS_TPP\master

By now you must have back ups of chunk0 data. If not, DO IT! JUST... DO IT!

Also. Consider this mod to be a disguise for Demon Snake. If you trigger demon snake using the short horn mod files, you'll still be permanently covered in blood.  (I guess. Not so sure anymore.)